Comment by phkx

The functionality included time-based rotation of the identifier that supposedly at least notably increased the effort to identify/track people over a longer time frame. I never dug into the details, but I figure that works better with short-term contacts and may break if you are in contact with many people over a longer time frame. Also, like contact tracking, it should be opt-in, so that you explicitly could act as ‚eyewitness‘.