Logging software uses GPS. If they jam it they can go off route or otherwise not have big brother watching them. I imagine it's becoming somewhat less prevale

Logging software uses GPS. If they jam it they can go off route or otherwise not have big brother watching them. I imagine it's becoming somewhat less prevalent though, as it's widely known they do it, enforcement has ratcheted up, and it's obvious when trucks just drop off the face of the earth all the time. It's not like 15 years ago when cell networks were much more sparse.