Hm, that may be something about your approach. Generally people are too drunk and having a good time to care, as long as they trust you. People reflect what you put out there, so if your attitude is “Hey, everything’s ok! I’m supposed to be here, we’re all having a great time, just keep on rocking with your bad self!” they will generally have their eyes pass over you, or see you, get a quick shot, and stop caring. If it’s just five people facing inward I will maybe just over a camera over or go for a long shot, but usually it’s not the right opportunity for a great shot.