We've done a $5 bounty with a $10 buyin and I would say it really screwed up the game.
It was a head hunting fest ...

You could come in second and make more than first if you took everyone else but first out.....
take two people out and you are a wash in terms of your buy in.....
Shoulda just played a plain old $15 tourney.
I love bounties. Just jigger the percentage so that it's like what hachkc said.