so, hear's one reason not to use your real name; stalker-campers. if a camper knows your name (and this has happened to one person i know), it's not too hard to get your address. while generally this is okay, there are some campers out there that you don't want to be in contact with, or...it brings up the same issuses as giving campers your address or email, except there is a level of added creepyness because, well, you didn't.

It also brings up privacy issues about your life outside of camp. if a camper learns your name, discovers that you are actually a dirty romance novelist (??), even if you are and were an upstanding counselor, it would reflect badly on the camp (granted, they hired you) even if it shouldn't. and possibly traumatize the camper. It brings up questions of how much your outside life (assuming you have one) is or is not part of camp.

Someone else mentioned parents calling up and harassing staff.

These are about as likely as someone being traumatized by the use of a nickname.