How do I make the fog lights work without the headlights

In some states it is illegal to have fog lights that go on without the regular lights. Not that you'll do this but.....some people pull up to a gas station at night, fill up, and then take off with only their fog lights on. Without having them wired to the rest of the lights the license plate light does not come on when only the fogs are on. I got hasseled during a vehicle inspection because the fogs did not go on when the rest of the lights were on. They made me take them off before they would pass me.