Any that have 'plans' means they KNOW where your tractor is. READ their 'Terms of Use', especially the fine print. The car insurance OBD-II plugin for cheaper rate deal alllows them to SELL your info to anyone they choose.
yeah I'm 70 and cynical ,but really, read the fine print before you buy.
None of these tracker will prevent theft of your tractor. It's easy to haul it into an enclosed trailer and poof, tractor is now MIA.
Consider making it harder for the thieves to drive your tractor away. Simple stuff like remove battery or primary fuse, remove a front AND rear tire, sit on blocks, put note on it saying' plug BOTH GD tires buy more wheel nuts'. Drop loader to ground, same with 3PH blade. Put on blocks and remove valve stems from the other 2 tires. Essentially you want to make it a real PITA for them to steal it. OK, so YOU have to spend an hour to get it 'up and running' but... at least it's still there.
All 'trackers' consume a lot of power and the more 'pings' the less time the battery lasts,even less in winter ( below 50*F )