Personally, I think this whole thing is likely a distraction. That said, why would they land in the middle of a city? You think they want to cause a riot? Hundreds of simultaneous heart attacks?
If UFOs started showing up over major cities without some sort of prior contact and announcement, that'd be cause for concern. We consider it a huge breach of security to have unauthorized planes in our airspace, I'd imagine that they'd take it as good etiquette not to be zooming around highly populated areas.