I really think that the keys are meant to stop someone from staring the tractor that could get hurt, like a child. It would be very, very easy to hot wire a tractor, since the ignition wires are usually exposed under the dash area. It really is not so much of a method to keep your tractor from being stolen, as it helps keep kids from starting them. I know that a lot of older tractors, and even my tractor can be started from the ground, and with the tractor in gear, so it is a big safety issue, since I have a little one at home. The best protection is a locked barn, or keeping an eye on your equipment and making it difficult for someone to drive one off of your property. You would have to have a flat bed ready, because as you know, tractors are not known for their speed.
