I think you guys forgot the "ONTO" you, the onto part already takes away like 50-70% of your creepyness. The guys will understand that your only a man, you can't help yourself and she's probably told all her girlfriends that she's gonna come onto you. The only thing you've really got to worry bout is the other girls that haven't got the knowledge that it was her plans and the people that don't know that she came onto you.
Other then that it depends who you with, just close friends and no ones gonna care might get a bit of joking from your friends but it happens to everyone, with a bunch of people you don't know could come off a little creepy but she came onto you, so no worries. unless it's like her first time drinking. It depends on heaps of sh!t make your own decision.
If she's experienced drinker and she's tipsy its all good, other non experienced drinker might think it's creepy but everyone that drinks knows that when your tipsy you've still got your mind, and the even more experienced with drinking girls will know that they always fake being a little more drunk then they actually are so it's completely ok.
Other then that this is petty bullsh!t the fact that you may have took advantage will leave the gossip circle after a week unless you keep doing it, just make your own decision, and why not get a bit tipsy yourself then you can get away with it all.
Just it doesn't really matter at all, you guys worry about gossip and rep to much.