I tell you who would be on to a winner, someone who came up with a cheap, small separate app that just broadcast position and notified by sound when another broadcaster was within XXX NM (user defined) and was able to show position on a map. Map could be simple enough, no need to be a WAC, this would solve the issue of different EFB users or, guys like myself who use an EFB for charts and plates and who don't use the flight plan options, or, to be honest only really use it when in new territory or doing an instrument approach. Also, be more likely to get everybody to use it. Could work similar to ADSB notification... Just my 2c anyways, i"mno software designer and if push came to shove, probably couldn't spell EFB...