And those cashiers deserve to be written up and fired if they keep doing. It does not matter what the customer bought or how much they held up the line it’s illegal* to violate their privacy. The store could, in theory, lose it’s contract over that. That was drilled into us when I was a supermarket cashier and I did enforce that on other cashiers when I was promoted to front-end supervisor. We weren’t even allowed to say “foodstamps” out loud. We just called is a “card” and were only supposed to say “EBT card” unless there was confusion.
I’d also have other customers ask me if X had used foodstamps and get pissed off when I told them it was none of their business (note I didn’t actually say “none of your business” until after kept asking a couple times.
It’s also illegal for a store make EBT customers use designated “Foodstamp Lanes” or not let them use any lane that takes debit cards (including Express & self-checkouts).