I can’t believe this still needs to be said.
Cosplayers are not there to be your pets, your pretend girlfriend/boyfriend, or your creepy grope fantasy. Don’t put your hands on them without permission, don’t take photos without permission, don’t bully them, don’t push them into corners, and if they tell you to back off, you BACK THE HELL OFF.
I am still hearing from Cosplayers saying that people won’t take a polite OR firm “no” for an answer. That’s unacceptable, if you see this happening, inform someone immediately.
Spirits run high at conventions. Some attendees are a little socially awkward, or aren’t really getting the boundary between reality and fantasy. None of those things are excuses.
Use your decency and common sense. If you wouldn’t treat people like that on a bus, don’t even think of treating them that way at a con.