I have seen a couple teens with pacis (they're called "dummies" in the UK), but that was a couple years ago. They were with a few friends and they didn't seem to give a second thought about it, whilst all the other people on the bus were just plain silent.
Camping near a river one day, and a man with his two daughters, approximately 8/9 and 12/13 comes walking along, and stopped to talk to me about how my fishing was going.
The OLDER girl was openly sucking on a pacifier, leaving it in her mouth and not even trying to hide it. As I spoke with her dad, she kept openly looking at me, obviously trying to judge what my reaction would be.
For the record, I ignored it.