I know it was a noob mistake but if I help one of you bros to not make that mistake it is worth it:

So I met this HB7 at the club and we have a really great time. I take her to a chilled area and tell her we should leave. That's when we get our jackets and attempt to leave the club. Me right in front of her.

Just as I'm out of the club I turn around and see her talking to some guy.

I still got her number that evening but I'm sure I could have got more than that.

TL;DR : title cuz she might meet someone she knows just before you leave.