That's the thing with an import allowed server, people can just import cheated chars and dinos. I've had less random pks on official servers than there.
So far I still haven't had any of my beds destroyed on the official one. And I have like 8 set up across the map, a few even without walls.
This is the way I see it: If you are playing on a server that doesn't allow imports, and get up to level 25 (the level required to build your own metal tools and start destroying buildings with them) or spend several hours taming a dinosaur that can destroy a building and finding a saddle for it (also requires some levels, not sure lowest level a dino can kill wooden buildings) then you have a decent bit of time invested on that server. At that point you want to keep playing that character, as he's over the initial difficult bit and can now build his own semi-secure houses and make nice things for himself.
On the other hand, if you just cheated a high level char into the server, with your high level dino mount (which doesn't even need a saddle if it's cheat tamed), you don't have much to lose.
In which case do you think someone is more likely to be a dick and go around destroying buildings and killing people, potentially making lots of enemies and even maybe getting banned if the server owner doesn't like it?
Now on pvp servers there will be raiders, but they will also have a base of their own. Which means if they raid too much you can probably get together some other folks also raided and raid them back. You don't see the people with nothing to their name just roaming around on a trex smashing buildings because they can - someone who can tame a trex generally has a base and a lot of time invested on that server. I actually saw this play out on the server I'm on (official 343). People started talking about getting raided by this one group, and one of them was like "Well why don't we raid them? I know where their base is. Anyone have c4?" Then they organized to talk over steam instead of in game. A few hours later I see someone else remark "Holy shit, those ____ guys got raided bad. Their base is in shambles."
-edit- In other news, the 175 patch notes look nice. I especially like the tribe governance thing, sounds like you might be able to organize it where people keep individual property and also have tribe property (which would be awesome for loose knit tribes like a b12 group). Crops grow twice as fast and resources respawn faster too.