I work in the aviation field. Never, ever, have I seen or met someone who intentionally sabotages an aircraft. In fact, when we do disable a non essential system via the MEL, it's done with the manufacturers and FAA approval via approved data. Furthermore, the information is made available to the crew via placards on the non operative equipment and clearly stated in the daily flight log / daily cockpit paperwork. There are known trends and known groups that specifically target aviation, all of us would do well to be alert for any irregularities. These groups regularly target everything from airline food all the way up to the flights themselves. As always, best to be alert and aware.