[Fester Chugabrew]

Cashier pushes a button. An electric screen drops down in front of all exits; a cage of sorts. No one leaves, at least confortably, until authorities arrive.

[Beagle8U]

Why not just throw the clerk into a cage full of wild animals? It would be the same thing if you lock them in.

[numberonepal]

Cashier pushes a button. An electric screen drops down in front of all exits; a cage of sorts. No one leaves, at least confortably, until authorities arrive.

It's not stealing until they leave the store. The authorities would promptly charge the store owners with unlawful imprisonment and/or kidnapping.