Constantly driving on the grass or dirt
I've never seen a show where the characters spend so much time off road in huge sedans.
I don't know if Hawaii had a lack of roads at the time or what, but even a lot of the home locations don't seem to have driveways, and a lot of the crime scenes are at cliffside which of course requires driving through wildlife refuges to get to, lol.
It really makes me cringe to imagine those undercarriages and bias ply tires getting stuck in the ground. I wouldn't even consider driving those cars in a lot of places they took them.