I disagree. These companies aren't total morons. I'm sure they've studied this thing exhaustively and calculated a slighter higher shrink and machine maintenance was cheaper than paying cashiers. Keep in mind, at the low end of the pay scale, the employer's total cost is nearly double the wage paid.
Some places may call the cops, but I'd bet that's a rare event. Look at it from the cop's point of view, they're going to get sick of that petty shit in a hurry, start slowing their roll when the store calls. Want an annoyed police force when your store has an actual emergency?
Most places in America, the big chains anyway, seem to have policies like I was trained with at Lowe's. No cops unless it's an emergency or they stole something huge like a $4,000 mower, and even then, call after they've left and give the cops the license plate pic. Never accuse a customer, not even an implication. Never block a thief from exiting or back them into a corner. They gave us some pretty slick tips on approaching someone we suspected, mainly consisting of chatting to make 'em nervous.
Always keep in mind when you see some crazy shit like the article you read, that makes news precisely because it's crazy shit.