I've seen, in places that get a lot of foreign tourists in the US, in particular, Orlando, big notes on the menu, or even the wall, about expected tips.

I remember, a few years ago, having to send back a steak in a steakhouse in Orlando and watching it sitting on a shelf next to the waitress for a couple of minutes, when it came back, while she chatted to a friend.

When the bill came, she had written on it something like "My name is Arlene, it is customary to tip 20% in the USA"; I added "I know" and left one cent.