Would you let a random stranger pay for your groceries if they randomly offered to?

I have helped people buy their groceries. There was a homeless guy I'd seen around and I was behind him in the grocery store one day. He was trying to put things back he couldn't afford, which wasn't much. I asked the cashier if she could ring it all and I would pay. It wasn't even $20 worth but he was thankful yet embarrassed.

As long as they don't want my ass after

Don't see anything wrong with it, but I'd certainly pay it forward.

I suppose. I would be caught off guard, but me, hoping the world becomes a better place than rejecting someone’s kindness seems counterintuitive.