Good question!
We have had bell abuse issues off and on as we're working on training Nikko... it's so aggravating!!! I would love to have a doggie door someday, when we hopefully own a house instead of rent and don't have to worry about getting our safety deposit back for the ruined door.
I'd love to learn more about how people with doggie doors train their dogs to use it (and not be afraid of it, too, just in case). Someday we'll have one!
Lauren & Nikko