Most purity rings are worn by girls and the majority of them have superior attitudes towards those who engage in premarital sex. By displaying this very personal decision to the world, they are getting on their high horse and judging those who engage in pleasurable acts. It's just another way for people to believe they are better than others.
Sally: Yeah and..
Nicky: I think I'm ready to take it to the next level an-
Elizabeth: OMG guyss guess what!?!
Nicky and Sally: What?
Elizabeth: I got a purity ring!
Sally: Yes, we know. We were there.
Nicky: Congratulations anyway. As I was saying, I think I'm finally ready to make a commitment to Ben an-
Elizabeth: Why don't you guys get purity rings too?
Nicky: We believe in premarital sex..
Sally: *nudges Nicky* and this one has a boyfriend.
Elizabeth: OMFG you guys are sinners! What would God think? Thank God I got my purity ring; it'll save me from your influences.
Nicky and Sally: Um, okay.
Elizabeth: Don't you want to be pure?
Nicky and Sally walk away.
Elizabeth: Dirty Whores.
Andrew: "Oh, its my purity ring."
Richard: "What does that mean?"
Andrew: "Just a reminder for me of my commitment to purity until marriage."
Richard: "Oh, well I don't believe in that."
Andrew: "Ok, well that is fine."