It really depends on the temperament of the friend.

One of my good friends, who's declared I will be his best man at his wedding, used to be the guy at the party scoping out the drunkest chick for the "easy lay".

I flat out told him I'm not inviting him to my parties because I know all the girls that come to my parties personally, and I'm "sick and tired of watching you take advantage of the drunkest chick at my party."

He's told me that hearing this, he almost completely wrote me off as an asshole and never spoke to me again. It was only over time, and by seeing how shaping up (being nicer to people, not being completely selfish or short sighted) he realized I was right. And I was urging him to be "better" because I knew he was "better".

TD;DR: Radical Honesty can work, has a low success rate, and will always, always, always generate resentment. People instinctually kill the messenger.