Depends on the part of the world. If you intend on turning off your furnace in Canada, you best be prepared to winterize your house too! (Lots of cottagers do this... indoor plumbing is flushed and water is turned off at the pump, etc.)

Without a thermostat you have no idea what the temperature is. We are talking about failure, not turning the furnace off.

Surely there's some reasonable duty cycle, like (I don't live in one of those places) 10 minutes on, 50 minutes off, something like that.

A burst pipe is preferential to a house that burns down.