I wouldn't say anything to anyone, but yes, it makes the person with the hickey look trampy. In the very least, it's a sign of sexual immaturity and at worst it's the sign of an insecure person/relationship.

Because it is, like, SO immature to enjoy someone kissing/nipping/biting your neck! Only tramps like something as kinky as that! People in secure realtionshps never leave hickies because hickies are always about branding your SO, and never the natural result of something that feels good. Seriosuly.

Also, anyone who thinks that people start covering their hicky's at age 16 has never been on a college campus.