Maybe happened once upon a time in the US, years and years ago in some hick town with redneck jumpers but seriously doubt it happens in todays industry. Would they ever be allowed into that aircraft again after the owner realized that they basically risked his aircraft for a practical joke? Insurance would be void and they would be liable if it crashed.
Rest assured, it still happens today, and I've never heard of anyone being banned from the drop zone because they shut off the engine on the way out. It's just not that big a deal.
If one can't hit the runway from fifteen thousand feet overhead, without power, then one shouldn't be flying. If one is concerned about practical jokes or fun at the drop zone, one is definitely in the wrong environment.
Jump pilots should be jumpers; it's hard to have the right perspective on flying jumpers if you don't skydive.
I've had jumpers hang on outside and refuse to let go until I shook them off, or stalled. One afternoon for fun, a freefall photographer and I staged fights in the airplane, each time terminating with him throwing me out (I wasn't driving at the time), to the wide-eyed stares of the tandems and students. Nobody ever complained. Horny gorillas, rodeo dives, tag, it's about fun. Pilots who don't understand jumpers probably shouldn't be flying jumpers.