We've been doing some work with this and it has gone pretty well. Make sure you set up the proxy certificate so that the notifications can also go to the lock screen on the iPad. You set this up in the same area as the push notification certificate in the JSS. As the same time we also enabled location services for the iPads by turning on iBeacons. I'd do all of this at once so that when a student opens the Self Service app they get both prompts and you can tell them to accept them. Of course, you can't get everyone but you'll get 'enough'. We timed this with rolling an app out via self service so that they'd get all of the prompts as a group which helps with getting them to answer in a useful way.
It's a pretty slick feature! The next thing we're looking to do with it will be things like teachers being able to send messages to their students in the evening like "Remember, chapters 2 & 3 need to be read before class tomorrow."
