Had this done to me recently. In Aldi of all places
First they wanted to check my bag for life, which was very clearly empty. Was told this is done "at random" but immediately made me feel like I was under suspicion. Check out girl tapped some sign saying they now check all bags-yet no one else had this before I was served so I got some raised eyebrows and nudges in the queue.
Then, I finish packing my already checked bag, had paid at the till and went to the little bench to put the shopping away. Go to walk from it when the sweaty, couldn't catch cold let alone thief, excuse for a security guy comes towards me, grabs the end of the trolley and demands to see my payment proof.
Girl on check out who was so quick to check my empty bloody bag wasn't so quick to give a receipt. I said "this is ridiculous now, first her with the bag, now you"
He got aggressive and demanded to see my banking app. I refused. He looked a bit lost then, he clearly expected me to be a wimp and not want the embarrassment, which I didn't. But as an ex-retail manager I knew he had no right to demand that
I turned to the assistant who served me and said "would you mind telling your colleague I have paid please, I think your store has caused me quite enough embarrassment for today, and then I would like to speak to a supervisor"
She nodded to confirm I paid and they made some bullshit story up about no supervisor on site. I hate confrontation but I was so cross.
I've not been in since because I'm damned if I'm going to be treated like that. Even when walking out the store, the guard goes to me "I'll be watching you from now on".
Goodness knows what that was about, I wasn't dressed like a chavvy oik but then he looked like the sort who would never dare confront a real thief.
I was livid!