I'm not a trucker, so pardon me if this is naive, but wouldn't a security lock like one of these defeat all but a fairly determined passenger? It wouldn't eliminate the problem, but at least it would push them to someone else's truck.
https://www.amazon.com/dp/B000Z36T6Q/ref=cm_sw_r_cp_awdb_t1_rIbMAbBENJKNF
The description and general appearance looks like they stuck their 410 core in something useful. Can't confirm, don't own one.