They know as much as you intend to assume 'full responsibility', it will be there mess to clean up. They are messy and stinky too. My friends daughter had one, promised she would take care of it, and that wasn't the case. The daughter eventually gave it away because she got tired of the stinch and mess.
Because when they were kids Ferrets were considered vermin and were illegal to own in some states!!! ferrets used to smell really bad because they have scent sacks like a skunk, but theirs emits through their skin..but now all ferrets have them removed before they go to the pet store!! So they do not stink anymore!!