How about your boss tells you to patrol a stop sign all day and count the number of rolling stops vs. full stops. Since you know your cruiser is GPS tracked, you're concerned being seen not moving for 8 hours.
First of all, no one would be assigned on such a contrived detail. Even if they were, they would not likely be there for 8 hours as there are mandatory breaks. And even if they were there for 8 hours, dispatch would know they would be out on a detail at that intersection all day, and would be periodically status checked to make sure they were still alive. And finally, what in the hell would be the problem with being tracked as being exactly where they are supposed to be?!
Honest question - what bona fide police activity could be chilled by GPS tracking their cruisers?