they never, ever check for tickets anymore in movie theatres, its so weird, you can so easily sneak in and they will never know
In my area, I find it's highly dependent on the theater and time. In the smaller town theaters during matinees or weekday screenings, they never man the ticket check. During big premieres, it's always checked. At the nicer theaters in larger towns, and at indie theaters I go to, you can't even enter the main building without a ticket. The bigger theaters block just after the ticket counter and the indie theaters sell tickets right at the entrance.