I usually run with K-band off, but I discovered that a few local yahoos (Sheriffs) run K-band on the interstate in Utah during holiday periods. So this time I had K-band enabled. I started getting a K-band alert in the open desert. I figured it must be a LEO as there's nothing else around. I sometimes get a fleeting K-band false from a passing car with a Cobra on board, but this alert was steady and moderate.
I drove for several miles and it kept increasing, but no LEO in sight. WTF? This went on for about 10 minutes and then the detector was at full alert for a mile or so until I figured what was the culprit. Some highway maintenance crew was towing a K-band sign in the back of their rig, tucked behind a tail gate and not easily seen, as it was stored laying flat. As I passed it, I could see the sign was still turned on.