I had almost exactly the same definition, but interestingly I let the skydiver go free, and I figured the tank would be okay because it was stationary (and I think in my head I assumed someone else had allowed the memorial!)

In the end, I only banned the car and the boat, and the boat was only really on a technicality. In retrospect, I might have been being too lenient, but I think it had a lot to do with just the stuff that I wanted to see in the park, which is pretty interesting from a moderation perspective.