"They could in theory add difficulty tiers, but in practice that may require more effort than they want to put in. Plus they'd probably have to rely on the honor system."

He pauses.

"Also, they'd could maintain the guns better." If only to prevent another otherworlder from field-stripping and cleaning the things for them. "But I don't know if they'd want to train their workers to do it when the object is to get people to waste their money on more tries."