So what do you think?

I would say, teach her proper husbandry, have her set up a proper enclosure for the snake, and if it's all RIGHT, then give the snake back. Some people just don't have any common sense, but do all right with detailed instruction. Give her a cage-cleaning schedule, too. Sounds like the mother is actually a serious hinderance in all of this. Print out a few things for the snake's owner, and then see if she actually reads them--that will help determine her real attitude.

I'd say, take a page from the ASPCA--give the owner a chance to turn it around, but then if they don't...that's when you throw the book at them.