Group Blocks on Twitter

My wife Tweets all the time.  Because she is getting more and more popular each day she often gets followed by strangers and sometimes those strangers are adult entertainers trying to hitch a ride on someone else's shooting star.  There should be a way to do a general block on twitter.  Like if you didn't want a bunch of Bieber crazy 14 yr olds following you because that's creepy, you could click a button and make your twitter account a little more exclusive.  You should be able to limit what you see and who can follow you based off a movie-like rating system.