It still goes back to the point that 99%+ of all jet owners and anyone that has assets of that value are already taking precautions to protect their investments. Their doors are locked, while the aircraft is locked in a hanger. People know who is moving XXX aircraft, and if it's not someone with the FBO/company, then it will look very suspicious and raise questions. There are many lines of defense to keep common criminals from doing anything. My point as I mentioned before, if someone really wants to, they will accomplish their goal regardless of security measures, the inteligence is where the stopping power is!