(...)

BTW, is there any talk about placing the ADS-B signals on high towers marked on aviation maps? That would be an interesting add-on to the system.

OK, I have found the answer myself. No need to include high towers/obstacles in the ADS-B system as they belong to the map information and many good software pieces actually give that information in flight with respective audio warnings, if necessary. Still, who knows, maybe drones could be helped in that way in the future?

My spontaneous question was a result of watching those recent amazing flights along the ridge with hundreds of power windmills.