They're pretty standard here in Japan. They look (and work) like wireless doorbells. At first it can be hard to get used to the fact that the waiter won't come over until you've pushed the button but after a while you really start to appreciate it.

Also, in the US I always felt slightly guilty calling a waiter over as if I'm calling him out on not doing his job. Here, if they don't have the doorbell thingy it's expected that you'll shout すみません！ when you're ready to order.

The other major design issue with airplanes is putting the buttons on a remote and then jamming it into the armrest next to your butt so you can accidentally hit it when you're sleeping or shifting around. It's the airplane equivalent of pocket dialing.