silverdale I would agree with pennylane
first of all it's just a first date and why would you necessarily put all your eggs in one basket for the sake of someone you've never met - so totally understandable that they might still be looking at messages or still looking at other profiles. You're going to go through loads of frogs before you catch the prince :).
secondly, I also go back and look at pictures before I meet someone
thirdly, I think it's worth clarifying what you do or don't do. When I first started, I used to say to people, I only chat/see/message one person at a time (just so they knew) but actually I realised pretty quickly that very few people do this. Now I say nothing. But I do also think by saying nothing, there probably needs to be a point at which you both agree it's serious and come off there. I am not sure what that point is but I do know with the one serious bloke I met on there, we did agree together where that point was and both came off it at the same time.
re first dates, I've done busy pubs, coffee shops, agreed to go on a walk near me (where I knew loads of people could see me, i.e. a public walk through a park etc.)
I think for women, it really does need to be a safe public space with a lot of people around