I was out shopping with a family member over the weekend and found that the Rubicon had just been crossed: The checkout at a retail store prompted for a tip.
I didn't see it myself (we were at a Five Below and I didn't need anything) but it apparently came up on the screen after all the items had been rung up. Not that it even matters at this point, but as an added absurdity... this was in the self-checkout.
The funny thing is, I think I actually welcome this. I've become a tipping accelerationist now: Please, prompt me to tip at the bank. Not just the teller, when I log on to online banking. Prompt me to tip when I pay my electric bill. Let's see how far this can go before it all burns down.