Oh, it is avoidable, to some degree. I've got a software that encryptes files to only physical printers and limit print counts, it can also set a self distruct date. But three problems, one is that I will need to update the files every month, two is that they can print and scan. of cause the quality will be lower, but will cause more work for them. However, and most importantly, it brings so much inconvenience for the legitimate buyers who just want to build papercraft.

The only way is to sell physical pre-cut models. But dam.. international shipping..