A lot of people think they got away with something but in reality customs knew but were trolling for a bigger fish. Triking is a big fish. Fines, surcharges and future hassle would be brutally painful.Has anyone seen the software they use at the border? Do they record a description of the vehicle you crossed in (or a picture?). That would seem to be an easy way to catch many things.
Similar to insurance fraud, they've probably seen it before.