They do this in Monaco as well. I read in an article a while back that some nonresidents have automated timers to turn on/off the lights, turn on the heating, water, etc.
That being said I'm happy to be proven wrong, but can we expect any sort of data to support a hypothesis? I'm not sure as I'm unfamiliar with Canada's policies on access to public data.
There may be some question with privacy (e.g. proof of leases/lessee), corporate-owned residences, etc. but I'm sure they've factored that into things. The big deterrent to lying about it is probably the magnitude of the penalty for doing that - it's kind of like Martha Stewart: she didn't do time for insider trading, she did time for lying to the FBI (about insider trading).
EDIT: and the goal isn't to make revenue, it's to free up rental stock. If all the money collected goes towards enforcing the system and 20,000 vacant units end up in the rental market, then the policy is a total success.
Yep. You can see that with wealth taxes. Most countries that have wealth taxes (e.g. France) make close to nothing from them, because it's inefficient to verify and collect all the data to properly levy the tax, and you need a lot of civil servants for that.