Are they traveling internationally to your property @Nick2906 ?
If so they will have to fill in a Travel Declaration at the Border.
However some places may under specific Laws require Property Owners and Businesses to have a Copy so they can pass those details on to the Authorities - usually it's to be able to locate people as they go about their lives traveling.
As a Host with a shared home arrangement I've never once had a Guest willing show me an ID.