I feel like this is one of -those- issues where there are solutions that sound great but so many challenges that make it really complicated. Principal of which, some people step away from the PC for long periods of time - military deployments, health issues, stuff like that. What is/isn't an acceptable reason not to play arma 3 roleplay game? Who will govern that? How will you verify the integrity of peoples' claims?
If you set a bare minimum then people will just log on and AFK just enough to meet that minimum, I don't think it's gonna have some revolutionary effect.
IMO, with the few extreme examples that I've heard about where this stuff is going on with sheds/v good location houses and has been for many many months, it may just require someone taking the plunge and just taking it and auctioning it off, returning the proceeds to the original owner. Yeah they will cry but it's on them. And if they are active enough they can win their own house back in the auction.