We’ve noticed in recent days that there are many more teens running around Dupont Circle than you’d normally expect. Local eateries have been extra crowded, pretty much every Starbucks is a no-go zone and the usual resident-enforced rules of Metro are violated at will. What gives? The North American Invitational Model United Nations conference kicked off yesterday at the Washington Hilton, putting District residents at the mercy of 3,000 high school students with hotel…