I don’t know why nobody ever thinks of stuff like this. If something is clever, imitations will be made. In an Internet-tied world, they’ll then be available to everyone.
To wit, some years ago, cities started installing special IR overrides on traffic signals at major intersections. These would allow police and fire responders to break through traffic and get to where they needed to be all the faster.
Well, guess what. Now you can buy knock-offs on the Internet.
And now cities are wondering if traffic signals will be tied up by people switching them to and fro, whether responders will be able to get through, whether all that money has been wasted, and — how do they detect a box that can be hidden inside of a car, and which, at the moment, is legal to possess?