I rent a basement suite where I live, and will be moving to a new one in a few days. My impending move has got me thinking that private property rights are meaningless if you can't own land.
Living in our consumer driven society, I have acquired much stuff over the past seven years. However, I found myself looking at the prospect of not being able to find comparable space at a price I could afford. Thus, I must divest myself of some of my possessions in order to fit into a new location. That's why the acquisition of wealth will not motivate a homeless person. What you can't fit on your back (or, if you're lucky, in your car), you can't possess. Of course property values and rent can change. Living in the city "on the grid" so to speak, you are at the mercy of a utility company to provide heat, power and water. So you work. You work to live, to hold onto that which you have.
In Canada, our Constitution does not contain any rights to private property. Some may say that those rights exist in practice anyway. However, even if you "own" property, the government has the right to tax it based on its value.
So the widowed grandmother must sell her property to pay the tax on it. Its not like there is a little spigot in her house she can turn to cash in on the speculative real estate market she's become a victim of. That why property tax is an oxymoron. It isn't your property if you have to keep paying somebody else for the right to keep it.