I've used this tactic on people before, and they've used it on me. Everyone wants to ignore a text until it says something that benefits them. You can do it with a negative thing too, but that's much harder. Stick with the positive bait and switch. That'll get them every time. What I don't get is this kid's lack of empathy. They say, "that was cruel," but you know what's cruel? Ignoring your parent's text.
A horrible prank to play on your kid is telling them you're going to get them a car when you're really not. It's downright evil. But it's also really fun. If you're a parent with a teenager, have a friend park their car in front of your house and put a bow on it. See what happens.