100g is a lot for the type of drones used there, it's comparable to their whole battery pack weight. Also, the power draw of such a transponder is likely to be significant.
Sorry, but unless it’s a toy drone, the battery weighs a lot more than 100g. I own almost 20 drones and I think only the Tello batteries clock in at that range in weight and it’s useless imho to a police department. My Phantom (nearly 500g battery) / Inspire (515g) / Mavic (~250g) batteries are all way heavier than 100g and the batteries I use for my S1000 are over 2,000g. That said, 100g additional payload is significant for everything but my S1000, but I had to correct the statement re: batteries.
As to transponder power usage, it would be very negligible compared to the power draw of the ESC/motors.
As to transponder power usage, it would be very negligible compared to the power draw of the ESC/motors.