Keltham wasn't expecting them to go off and immediately start setting up games to simulate the thing he was describing despite the absence of actual jellychips, he'd sort of wanted to see if imagination would be enough, but he's not going to stop them if they do that.
He draws the line at the wrist-slaps, though. "The point of positive rewards in this case is that there's an incentive to play the game at all," Keltham says. "If you tried paying dath ilani kids in negative wrist-slaps they could avoid all the wrist-slaps by not coming to class. It's like trying to buy shoes at a shoe-shop by threatening to wreck the guy's shoe-shop unless they give you shoes. The guy doesn't want to be part of the whole system then, and now they have an incentive to call the town guard... okay, 'town guard', sure. And anybody else who sees that's how you operate has an incentive to poison your shoes and send you to the afterlife early before you come around to their shop. When you're trading things the other person actually wants, they want the whole system to stay in place, which is what makes stable equilibria possible. It's an important difference!"