There's almost always a POS at the entrance of any restaurant, if nothing else for take out orders. If I have to wait more than a few minutes I just walk up and have someone ring me up. Maybe that messes up the order of things, I don't care.
I do this in the US and wonder why others dont. I noticed years ago all restaurants had registers up front anyway so I tried and they took my payment and everywhere else since is pretty much the same story.