Glass is pretty scratch-resistant. You can take your keys to an iPhone or iPad as vigorously as you'd like with no ill effects. I've demonstrated it to several

Glass is pretty scratch-resistant. You can take your keys to an iPhone or iPad as vigorously as you'd like with no ill effects. I've demonstrated it to several people, to usually shocked responses. Cat claws don't do anything to windows, they're not going to hurt an iPad. This is also part of the reason why Apple's stopped selling screen protectors - they're as useless as Monster cables. They don't actually help anything, and they get scratched easier than the screen does.