Harmless as they are, no one wants to buy the snake house. Also, garter snake waste can smell like old fish and they go ALL the time. Hundreds of garter snakes is definitely going to smell funky. Sad that these little dudes are probably going to lose their home though :/ I'm not sure how well they handle finding new hibernaculums or even being moved to new hibernaculums. I know it's more possible than with some animals where it's absolutely not an option (incl some species of bats), but they would normally return to the same one every year.