there are plenty of them here in NY. or, they'll ban before/after the busy period. you can't just buy a $3 cup and sit all day at a table that's costing the operator $10/day to lease. It's also really obnoxious, it makes a place seem boring when people are sitting around anti-socially with their laptops pretending to be studying.

It's a pretty unique American thing -- you can't just sit quietly, you have to always seem busy -- kind of like eating lunch alone.