Mandatory transponders on drones might not be the worst idea. I'm sure soon enough police will learn to look for the signals. Many drones are 2.4ghz something

Mandatory transponders on drones might not be the worst idea. I'm sure soon enough police will learn to look for the signals. Many drones are 2.4ghz something something. What if airport police monitored the frequency around the airport? Then use signal finding to capture controllers?