I had a hard time coming up with a name for this, so if anyone has any better ideas, please let me know so I can update it and set better search tags.

Our kids have a very hard time turning off the bathroom fan after they finish using the bathroom. We find it constantly left on overnight, etc. This simple gadget fits over the light switch and is held in place with a bit of hot glue (making it non-permanent). It will allow the bathroom light to be on without the fan, the bathroom light to be on with the fan on as well, but will not allow the bathroom fan to be left on when the light is turned off.