That is not a pasty, that is a piercing. Even my 16-year-old daughter knows that is a piercing. (In fact, I am appalled at just how much my daughter knows about such piercings!) At least one of the news reports I heard last night did describe it as a piercing, rather than a pasty. Ouch.
One of the news channels was also brandishing a news release from MTV, dated some time last week, that said there would be a "shocking moment" during Janet Jackson's performance. This is being displayed as proof that it was planned, rather than accidental.
I'm still not sure, oddly enough--in all the replays, she sure looks shocked that her tit is suddenly hanging out in the open--she covered it pretty damn quick, too. That news release from MTV is pretty damning, though--in spite of all their apologies today.
Caitlin tells me that thing is called a "nipple shield." Ouch.