Ventti How can FLARM, with or without OGN, ‘see’ anything that isn’t itself equipped with some sort of electronic conspicuity device? In the UK at least there is no requirement to carry anything in Class G and many planes, gliders, para gliders, kites and even large model aircraft would be ‘unseen’ hazards. Although there isn’t too much manned flight below 500’ where I think the drones will typically operate aircraft take off and land at ‘strips’ which may not be marked on charts, gliders land in fields and ridge soar below ridge top height etc etc.