Forgot to say, my aunt went to Tescos to do a normal shop then trundled off about her day, only to find a message from her car repair garage on her phone. Calling back she found out that some bright spark in Tescos had her down as a shop lifter but didn't stop her on her way out of in the car park, although she took her time and also stopped for a chat in the car park, so not exactly a tough person to approach!
Instead they took down her license plate and the contact details of the break down garage she used, which was visible in the cars front window on a sticker of some kind.
Having done this they then phoned up the garage and told the garage that they were attempting to track down a shop lifter who had stolen a huge amount from that store 'though you'd never think to look at her', and they then asked the garage to 'run' the license plates and give the full name, address and contact details as the store staff needed to identify her!
Luckily the guy at the garage had a modicum of sense and refused to give my aunts details. Apparently the supermarket employee got angry at being refused and actually said that he'd done the garage a favor letting them know about this thief so she didn't steal off the garage too, and also as one shop to another shouldn't they be helping each other out (you know, from one major national supermarket chain to a small independent garage.. Err).
The garage person was so incensed at this that he phoned my aunt to let her know that this store was behaving so shockingly.
My poor aunt was really upset, that some complete stranger had made up a story about her, and was going round telling people that she knew and had to face again, that she was a criminal! Luckily the garage had known my aunt for years, and were about as shocked as my aunt was, but really, it was awful behavior and my poor aunt was too humiliated to take it further.
She went round asking the people manning the tills in shops to double check the receipt matched what she'd bought as she was so afraid of it happening again. It felt so personal to her, and very hard to put it down to a revolting wannabe sleuth behaving illegally in his quest to bag a thief, or brighten up a dull day by breaking a few laws around personal data, defamation etc.
This was a couple of years ago but still makes me seethe. Rest assured OP, you're not the only person to have been upset by this 