Bag checks in stores: Is that allowed?

Questioner

For a few weeks now, the cashiers at the local supermarket have been asking if they can look in your bag. There are posters on the door of the supermarket and at the checkouts explaining this. My question is whether an employee of a store is allowed to ask this if there is no suspicion that you have stolen anything and do I have the right to refuse?

Lawyer

Yes, if the house rules are clearly stated and they are by sticking them on the door, then those house rules including a bag check may be carried out. You may refuse this but then the store has the right to call the police.