There are a lot of very loved sugar gliders that drown in toilets, even though their loving caretaker knows about the risk. It takes just one time forgetting to close the lid... Here is the suggestion, as designed by my brother Alain.
Attach a sponge to the water tank of your toilet with some poster stickers (I use the thin foam ones that is like double sided tape) in a way that the lid can't stay open. When the lid is up, if you don't hold it up, it slams back down. You may need to fiddle a bit to find a sponge the right thickness or width. Why a sponge? because it's squishy so the lid can still be pushed back while you are sitting. About the really annoying noise of the slamming down of the cover, I just put little felt pads under both the seat and the lid. It mutes the sound enough to make it much more bearable. (Also, as I don't like the slamming anyway, I very quickly learned to close the lid myself every time).
Roommate or not, there is no reason from then on for the toilet ever to remain open, distracted roommate or not.
I hope this will help some of you.
I'm writing this with a compassionnate thought for Anna, whose dear baby just drowned this way, and in the hope that this will save some sugar glider lives.

Follow Ups:

• Also a great idea for homes with small (not toilet trained) kids! n/p Shannon 21:57:21 05/27/2000 (0)
• Re: A tip, if you're worried with toilet drowning... Rosie 08:28:08 05/24/2000 (0)
• Actually, thats a good idea. Kim 22:17:44 05/23/2000 (0)