Some of the pretzel/cookie carts at the San Diego Convention Center now use that one NCR device (the one I've seen a few other places around here and is supposedly at some Waffle House locations). Unfortunately it looks like it's only used for tip selection; the cashier has to swipe on their end. They even went as far as to tape off the contactless logo and swipe/insert readers since I guess people have been trying to use those.

On the other hand, there's an unmanned burrito cart there this weekend too. Tap your phone or card (I don't think you can insert or swipe, or at least I didn't see a reader that could do either) and it automatically charges you for whatever you remove from the heated/cooled bins. Thinking about it, I should get photos next time I see it tomorrow or Sunday so you guys can see what I mean.