Our generac is bolted down and anchored. Had to be lifted into place via crane.
No one is going to try and take it.
I've got a GE whole home gen and although it is heavy, it isn't bolted down to the slab I had poured for it. I did locate it around the backside of my house so it could not be seen from the road but I'm sure it could be heard from there. Now if someone were to decide to take it during a wide scale outage, I'm afraid I'd have to go outside and discourage them. I would not do that unarmed.