Temporary Front License plate Bracket

I've dabbled with this idea before, but never got any ideas that I liked. I hate the look of the T-bird with a front plate on it, so I don't have it mounted. I haven't driven with front plates for years on numerous vehicles even though my state requires it. HOWEVER...now the city of chicago must have a Lojack on my car or something, cuz even when I park legally on the street, within 20 mins (literally) they find my car and give me a parking ticket for no front plate...50 bucks per..ching ching, thank you very much.

What I want to be able to do, is have the plate and/or holder in the trunk, and if I park in the city I want to be able to easily toss it on...HOWEVER, if I forget to take it back off, I don't want it to fall off when driving. The last resort would be drilling holes in the bumper cover, so the grill seems to be the only option. Before I was wondering if there would be a way to use magnets.

Anyone have any suggestions?

I guess the problem is because so many states don't require them, so it would look odd on a car if they designed the front with a plate in mind, and then didn't have one on the car.