If we're speaking about privacy, then ADS-B is just one element of concern. The FAA is now finalizing new Remote ID regulations that will require all unmanned aircraft over 0.55 pounds to be identified and tracked in real time, with data shared back to authorized data aggregators. This is a major concern to hobbyists (think first person quad-copter racing), because the details of the proposed rules make it virtually impossible for hobbyists to fly amateur built aircraft, while giving cart blanch to commercial drone operators (ie delivery services) to fly anywhere assuming they have the resources to comply with the new Remote ID rules. The FAA is essentially saying they have the authority to regulate all navigable airspace, and since UAVs can fly inches from the ground, they are claiming authority to regulate who flies an inch above your own property. The rules are open for comment right now https://www.faa.gov/uas/research_development/remote_id/. A good summary is to read DJI's point of view. https://content.dji.com/we-strongly-support-drone-remote-id-...