Hmmmm.... I think we're going to need some proof on that one. Post a pic. Ha ha ha.. nah I'm kidding...
Anyway, it's been my experience (from watching my friends and other chicks at the bar) that girls pretend you're not there and avoid eye contact for two main reasons... (WARNING: Generalization Alert)
1. They are waiting for you to go up to THEM... they don't need to make eye contact with you, they don't need to acknowledge your existence. If they are conceited enough, they will expect you to approach them anyway without it. And if you don't, they figure they are hot enough that it doesn't matter if you approach them or not... the next hot guy will.
2. They are pretending you're not there because they are hoping that if they don't acknowledge you, then you will go away and leave them alone. They are afraid that even the slightest accidental glance in your direction will encourage you and then they will have to deal with you. (This could be because they simply aren't interested or because they are very insecure).
Yes I realize that 1 and 2 are basically complete opposites. Aahhh... the insanity that is woman
My opinion is that if the girl is really giving you the total cold shoulder, then don't waste your time. If it is because of reason #2 then it's probably not going to happen and you are wasting your time. If it is because of reason #1 then the chick is probably conceited and possibly a pain in the @ss and who wants to deal with that? The "non-hot" ones might be aggressive, but all you are looking for really is some eye-contact right? I'm sure there are plenty of hot or semi-hot chicks that won't ignore you and pretend that you don't exist.