The approved permit drawings for our pool show a 5' fence is required. A 4' fence was constructed and the permit was successfully closed. No idea wtf happened.I am no pool expert but I think the classic permanent above ground pools that are higher may get around some of the fence rules if the sides of the pool are high enough to prevent easy climbing and deck/platform has a tall enough lockable gate and railing. Maybe the taller sides and the deck provide all the required restricting access requirements.
For the lower sided inflatable/temp pools it will come down to someone complaining, specially if it is out of general site from the street. Pretty much like any artistic license interpretation of the local bylaws..... can't see it, no one complains, no enforcement.
For MP's pool, I am assuming it has a stepladder to get in and out. I would put the entire ladder in the pool when I wasn't using it. Makes it harder to get in and gives them and island to climb on in case they are resourceful and manage to get over the side.