First dates are filters to determine if someone is unsuitable. It is why you always, (well almost always), keep a lot of the real you hidden, selectively revealing bits that are hopefully interesting but not weird. A person who states his or her intentions from the get-go is looking to be rejected. And yet, stringing someone along is not honourable. And so, there is this delicate dance, which hopefully results in either heading towards “being serious”, or moving on before it is userous.
Something else to keep in mind is that men tend to be driven towards sex over commitment, (and no that is nothing new). Men also tend to be more romantic while women are more pragmatic. I hold that being female with the attendant challenges of providing for children in a very direct way brings with it less risk taking and a more cautious mindset. All this is a long way of saying that I agree with your point that men are more likely to string women along than the other way round.
If a date is a right-off, I usually know, and I expect the other person does as well. It is when it falls into the in-between zone that things become difficult. If it falls into that area, I would prefer to go out a few more times, but then as that becomes more and more established, a few more leads to a few more, and there is a feeling of being vested in a relationship, (even if it is delusional.) These are the things that make dating tricky, and it is what makes a breakup tougher after a year than a month, or a month more than a few dates. Most men, even when they realise this is not the woman for them have trouble calling it off. They don’t want to be a schmuck, and yet by not addressing it when they know, they prolong a deception and make the eventual breakup worse. Men are not alone in this, though I expect it is more common for men.
Bedroom and dating ethics could fill a book, and in Western society the rules or protocols are all but non-existent. In an odd way, you may find the traditional way of arranged marriages far less bewildering. At least everyone understands the rules, the process, and the outcome, without that particular angst which results from the under-defined mating rituals of the West. Somehow we muddle our way through, one way or the other, but look at all the collateral damage that is often left in the wake of the Western way.
One thing that is useful is having a clear vision (in broadstrokes) of what you want. The other thing is to always treat those you date fairly, including being honest when it is the right thing to do, and keeping your own council when it isn’t.

For me, this is a question of what the default position is. If we all generally believe and understand that a date or a relationship is for the purpose of evaluating marriage as an option, then yes, if you’re that crazy outlier, it may be your social responsibility to slip, at some point, in that you’re not looking for marriage. (It’s tougher, of course, if you ARE looking for marriage, but not with that particular person.)
But is this assumption-of-marriage world the world in which we live? It’s not the world in which I live. Perhaps it’s regional (I’m in New York City), but I think it’s safe to say that not every pairing, even for bona fide dates and relationships, contains even one person who thinks they may marry the other.
My opinion: people need to take it upon themselves to ask when they want to know. The other half, of course, is that people also need to answer truthfully when asked. You’re setting yourself up for disappointment, an unpleasant surprise, and wasted time if you simply assume that the other person sees potential for marriage in your future if you’re still seeing each other.

“You’re setting yourself up for disappointment, an unpleasant surprise, and wasted time if you simply assume that the other person sees potential for marriage in your future if you’re still seeing each other.” Really?
I mean, although I’m the girl who usually feels like a guy in relationships, I have to say that I just don’t see the point in dating without the belief that things could move toward marriage (not that I’m saying any guy who gets a second date is someone I want to marry but is instead just not cut from that list yet). Having random hookups are one thing…but any kind of emotional investment with someone you know you don’t want to be with seems like emotional self-abuse and in the end a disservice to the person you do end up being with (if you think you want to be married some day). Because if you know you want to be with a (for instance) Indian Hindu woman, but spend your whole dating life in relationships with blond Europeans, you’re ultimately putting even more questions in the heart of your future spouse. Yes?

I agree that the goal of dating is marriage however I think a more intermediate goal of dating is self discovery through a process of trial and error. Through the process of dating you learn a myriad of things about yourself. This process will ultimately lead you to ‘the one’ (in theory at least). I doubt that most people go on a first date with the presumption that they are going to end up marrying their date; the odds are stacked highly against it. (Sidebar- if all, but hopefully one, of the individuals you date ultimately end in failure why do we get so excited about first dates? Not to be a cynic, but the odds that your next date will be ‘the one’ are steeper odds than winning the lottery.) I think that most people go on dates in search of that perfect person fully aware hearts will be broken and time will be lost in the process. Nonetheless, through trial and error we come up with a checklist of characteristics that we are in search of for any future partners. Any subsequent date you agree to go on will either conform to your master checklist or won’t. If they don’t then that means you are either willing to have history repeat itself or are willing to compromise.
That being said, I think there is a BIG difference between what characteristics you want in your partner and what characteristics that you are expected to want in said partner (via the norms of society, family, religion, culture, tradition, etc). Sadly, I think most people place a higher value in the ‘what is expected checklist’ because people care too much about what other people think and fail to make a distinction between two categories. Nonetheless, this brings about two possibilities.
The first possibility is when your ‘deal breaker’ quality is listed both on your personal checklist as well as the what is expected checklist. If a person’s personal requirements matched with the requirements that are expected of them to have, then I highly doubt they would even consider going out on a first date with an individual that doesn’t satisfy the requirement. In the rare instance that they do accept a first date with an individual that doesn’t conform to their matching checklists, then I think this type of person should be upfront about their intentions.
The second possibility is when your purported ‘deal break’ quality is listed on one checklist but not the other. Here, I don’t think an individual should state their intentions on a first date. As previously stated, I strongly believe that the goal of dating is self discovery, and the process of finding ‘the one’ is that of trial and error as oppose to exact science. When the two checklists don’t match up I think there can be room for compromise and your purported ‘deal breaking’ quality can be overcome by other amazing qualities the date holds. In light of this, I think people will be surprised by what they learn about themselves by dating someone that, in theory, is all wrong for them. To preempt this, by stating your intentions outright, would hamper reaching the ultimate goal of dating- finding the one. Plus, you never know, the person that you thought was all wrong for you might end up being ‘the one’.