I bet in half these examples, if not more, if the guy tried to follow up on the "obvious come on", the girl would have backed out in 2 seconds.
A lot of times girls are just practicing, they want to see how desperate the guy is, how he would react to getting sex, does he have any other girlfriends, etc.
I've had quite a few hot girls bring me back to their apartment, and nothing. I've had girls come back to my house, on the couch 2 hours watching a movie, make like 5 moves, nothing. I've flown across the Atlantic Ocean for girls I've known, then when I'm there I made a move, nothing. And got in trouble for moving way too fast. I've been in hot girls bedrooms, nothing. I've been in Maxim model's houses, nothing. I've dated top ballerinas, nothing.
Men, alot of the time, girls, especially hot ones, will *test* a man to see what he will do. They have no intention of doing anything with him.
Be strong.