The question is partly, I guess, directed to the CRA, given that they are responsible for the administration and enforcement of the tax, but perhaps I can comment briefly.
The form is seven pages long, but a significant portion of that is listing the exemptions that are available to property owners. If someone is entitled to an exemption, I'm under the understanding that the CRA's policy is that the value of the property does not have to be provided in the return. Basic property information is required to be provided—the name of the owner, the address of the property, and things like that—but the information that's being requested is actually fairly minimal.