If they did notice it, they would more likely just send it back without repairing it than impose a restriction on the console or uninstall it themselves. If the repair was purely hardware-related they probably didn't check for that, and the underpaid employees responsible for handling the repairs typically have better things to do than check individual units for unauthorized apps. They probably just replaced whatever was broken, gave a quick glance to see if it was working, and moved on to the next order.