I have a pal who plows for the state, they put a GPS in his vehicle.
Now he has to park under an overpass to sleep.
Won't work....the record logs will simply mark where he disappeared from GPS view, then how long it was before he came back into GPS tracking view....the null point of the tracking plot would show exactly where the over-pass is. Tell your friend he needs to dope out a different strategy!
I don't know a thing about these systems, but if it does not also provide a way to review the route a vehicle took and how long it took to get from point A to point B, I would be surprised.
It should not matter how long he stays parked under the bridge, if they can tell it took two hours to make a trip that should have taken 10 minutes he will soon have to answer some questions