Most people who trow out protection messages are not in a position to protect anything. They're either way too high level, or really not that strong. I've been bullied by a few people saying they have strong protection, but it was never really a problem, since I just killed their protection... Besides, I guess I had some backup of my own.
I mean, the only thing you lose on this game by pissing someone off are stats.
I think it's a cool idea, but I don't think it's very practical, and I think it will clutter the profile page more than necessary.
//Formidable - DeathWish MGS