That would be a problem. Booby trap the place...? (Kidding.)
Well, there are solutions to that too... satellite. I’m sure that a discussion with Zoleo, inReach or Garmin would identify some possibilities, but they likely won’t be cheap.
Regardless, what do I do when i see someone there? Police too are hours away.
It almost is a case that one is better off to leave the doors unlocked with a note that says “Look, I left the doors unlocked so you didn’t need to smash in. Please tidy up after yourselves and leave the place nice and clean.”
If not that, then yes..... booby trap the place.