[Ayrahb]

I've heard of people painting every wall and ceiling in the suite black before leaving, but it probably wouldn't make them cry. This might be too weak for what you are looking for.

This one depends on the type of business she is running: many of the smaller landlords don't report their rental revenue to Canada Revenue Agency properly and reporting her would really mess her up. Nothing like a good audit and subsequent tax bill to get her back legally.