alt Hacker NewsThey're easy to find, but not necessarily with stuff from off the shelf. Professionals with the right equipment though have no trouble locating them. The FCC is happy to hand out 5 and 6 digit fines for operating a GPS jammer and has fined retailers tens of millions for selling them.
If you wanted to exactly pinpoint it with a single device sure, but I'm thinking of a map where nodes just report that they are experiencing jamming, and then with the whole network you can see a radius of the jam, see it moving around, and assume it's somewhere in the center. All with cheap off the shelf hardware.
The police could probably combine this data with license plate scanners and see the single truck that always exists in the jammed location.