It comes from your assertion that "Private parties can't demand ID." That was your claim. I'm saying that as far as I know private parties absolutely CAN demand ID. Including for "routine transactions". And if you don't cooperate then you don't get to do the transaction.

You seem to have just completely reversed yourself with this post so now in turn I'm not clear on what your first one was for. If you were somehow conflating "demand" with criminal penalties or force then that's a weird reading, and also this entire discussion is purely about a business transaction. They didn't arrest her, they "jsut" didn't honor her ticket and booted her, which is what people are (reasonably IMO) concerned/upset about. But refusing to show ID wouldn't have helped with that quite the contrary, even places with zero such tech may require identity verification for a transaction and ID is the only widely existing low friction way to do that.