It's simple enough- don't buy pills from anyone at the event and don't sell any extras, even if you meet some nice kid and they get all buddy buddy with you and ask you if you can spare some. It's just not worth it. Equally, even if you're rolling your face off, there's no reason to tell strangers that you're rolling or you took pills. And if anyone asks you if you know where to score some pills, say that you don't, even if you do, just to avoid getting someone else busted.
That said, you're just over analyzing it. Just keep a low profile and you'll be fine. If you feel the need, just pretend like you have no idea what ecstasy is, where to get it or what it does to you, even if your eyes are the size of dinner plates and you're chewing gum like your life depends on it.