This MT fleet telematic system seems quite reasonable to me and shouldn't cause any issues to normal drivers. But it will identify those who flout the law - and quite rightly so too.
As for GPS jammers, I've occasionally encountered them on motorways when some white van man has one fitted, which has then confused my SatNav. In the US, one idiot was fined $32000 for using one:
GPS jammer costs driver $32,000 after interfering with plane signals - Telegraph
Serves the bugger right and that should serve as a warning to others...
