And how much do your 'Occupancy Police' cost to administer such a system ? If it relies on a property owner filling in a form, they're just going to lie to avoid the cost and without someone going round to every single house and monitoring it for weeks and months of the year, you have no way to detect people avoiding the tax.

Super high property tax when I'm not there? Simple, employ a cleaner on some minimal wage and let them stay there when I'm not in town. When I'm in town, put them up in a hotel. I'll probably still save money on the property tax and I can claim to be a caring employer, helping with employment in town. The city council are evil job destroyers by sticking me with huge taxes.

Scotland implements a 'second home' variant of their 'council tax' [a weird name for property tax]. Depending on area, it's a locally chosen multiple of the standard tax. But that's based on whether people declare another property and there's a lot of overhead in policing it. I doubt if it actually raises any extra net income.

But what if your empty property is actually from a relative who recently died and the estate is being finalized? Does that get hit too?

It always sounds simple to just slap extra taxes on rich people (who always happen to be defined as someone other than yourself), but that often leads to unfairness to decidedly non-rich people.

Rich people always find a way round these things - they pay lawyers and accountants to make sure they can. No public policy will ever fix that.