There are hundreds of ways to secure your tractor in the field.
But if they want it bad enough, you'll be calling your insurance agent.
Quick tips,
You can disable the electrical system by hiding a switch to prevent starting.
Best way I've found if I had to leave it for a few days is just take one of the front tires off. If you have a FEL its quick and easy. If not just take the battery with you.
Keep searching for solutions and you'll find what you need.
My biggest fear is not taking the tractor but a knife blade in the tire or sand in the fuel tank
Hope this helps /forums/images/graemlins/smile.gif