I think you are on a bit of a tangent.
If I'm robbed, and the criminal gets injured.. it's not automatically my nads on the chopping block.
Well.. it may be in some communists states.. however.. there are some states where the victom actually has rights...
soundguy
In Oklahoma, Texas, Arkansas and other "FREE" states if during a confrontation with a would be thief the thief assaults you (don't they always???) and fearing for your life you defend yourself with deadly force there just isn't much of a problem for the intended victim (now survivor.)
If you defend yourself properly , as taught in the state lisc concealed carry classes and the result is the attackers death, oh well. All the classes I know about teach a double tap to the center of mass to stop the threat with follow up shots if the attack hasn't been stopped. Two shots to the center of mass have a good chance of being lethal with any gun worth carrying.
Alarms can be reasonably designed such that they are virtually impossible to be defeated. They work on the idea of periodically sending a signal that they are OK. If the signal stops being sent, such as the bad guy shoots the electronics box, hits it with a sledge, or whatever that sets of the alarm condition. Whether or not the response to the alarm condition is adequate in either arrival time or force is a separate issue.
A remotely located tractor (and many not so remotely located) is/are subject to theft, irrespective of the alarm system, taking the wheels off, removing the steering wheel, secret switches and or valves to disable fuel or electronics. So long as the thief has an adequate tilt up trailer and sufficient physical access virtually any equipment can be taken rather quickly and easily. Starting and or driving the tractor is NOT required.
If your tractor is harder to take than most in the surrounding area it is less likely to be taken but that is no guarantee.
RF links are pretty cheap and reliable and can be easily used to construct the "I'm OK sort of system that is virtually impossible to defeat if your tractor is parked within radio range of "civilization (or your residence or...)"
For many folks, insurance is as cheap or cheaper than a decent alarm.
Pat