Indeed. When it detects something, it really is there. However, when it doesn't detect anything, it doesn't mean no aircraft are in the area. It can't be relied upon in that respect to prevent midair collisions with low flying aircraft that are not broadcasting ADS-B. Personally, I'd rather use my eyes and ears, and keep it turned off, as the warnings are far too invasive and for aircraft that are too far away, or way higher than I am flying. Fly as low as you can, which is where the best views are anyway, and it becomes irrelevant. IMHO, it's more of a marketing gimmick than a useful feature. No drones are broadcasting ADS-B. It's of no use in avoiding other drones, and that is the biggest risk when flying in popular areas.