There's a BIG difference between the female impersonators that you can't tell are males, and the type of drag where it's obvious the guys are guys (they haven't shaved, etc).
Female impersonator = RuPaul
Bad drag = Milton Berle
http://www.lucyfan.com/miltonberle.html
The second would seem to be a bit more likely to offend, but as a woman I don't really care about either one.