The growing issue in some cities with the lines is black/grey market activity. Nearly everyone in the front of the lines in New York were buying them to then immediately hand off to a handler somewhere. Most end up back in China being sold before the official release there, or in a few other countries.

Some of the others at the front are simply there for the publicity. Often wearing a shirt for advertising when the media comes around to interview them.

Vastly different then a few years ago when the iPhone was a new concept. I personally haven't bothered with the lines in ages, instead preferring to preorder and have it shipped. Will likely be preordering whatever new iPad comes out next month, to hand mine down to family members.