You could put in a Vision Pro, program it for autochangeover, set upper and lower temperature limits (can't set cooling lower than "x" and heating higher than "y"), then do a partial screen lockout where the tenant could only run the temperature up and down. If I recall correctly (I installed a slew of VP's in my last facility and did the partial screen lockout...but it's been awhile ago now) the partial screen lockout won't allow the system to be shut off or placed strictly in heating or cooling mode by the user...only the person that locked the screen and can unlock it can make these changes.
I think a cheaper way to go is to watch the weather reports for the onset of freezing temperatures. Before it really sets in, send a reminder letter to tenants of the clause in their lease (if any) that they must maintain minimum air temperature in winter or be held responsible for damages.
In the end, there's no stopping irresponsible tenants. Even if you went with the VP and installed it, a tenant could simply switch off the breaker to his furnace, neglect to pay the power bill, yank the stat off the wall and smash it to smithereens, or set the place on fire and laugh hysterically as he flees on one of those super fast rice rocket bikes that the cops can't catch up to as he pops wheelies all the way into the next state.
No...you'd never know I used to work in the apartment industry.
Electricity makes refrigeration happen.
Refrigeration makes the HVAC psychrometric process happen.
HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.
A building is NOT beautiful unless it is also comfortable.