If she had dementia bad enough to forget to pay, how was she walking home alone?
Have you never accidently walked out of a store without paying for something? I have, just last week - walked out of Lowe's with a pack of drill bits that I had stuck in my back pocket while I was shopping. And I was still able to remember how to get back to my truck. And yes, I went back in and paid for them.
Yes I walk out of places with other peopleโs schit all the time.