If you're going to a reputable piercer, one who you really trust, I think that they'll be straight up with you. When I went to have mine done, they WOULDN'T do it for lack of a lip on my navel, and said why would I want to spend the moenney if it was so likely to reject anyway?
Still bummed about not being able to do the navel, but I got my tongue done instead that day (had been planning on doing it anyway) and REALLY love that one, so no harm done.
~kristin

NSS 45659 N3ZDF USSF 8
http://www.wam.umd.edu/~viperkjp 'If you drink two beers and three shots of espresso, there's a twenty minute period where you can climb anything.'