To be clear, you have to be running "with" (determined by algorithm) another person to be tagged. It doesn't tag every person that you cross paths with.<p>Strava's unique selling point is that it is primarily a social app, and secondarily a running app. Global leaderboards require users to make their activities public. So having privacy issues is par for the course.
Reminds me of when Strava routes were disclosing info about personnel & physical structures of military bases: <a href="https://www.theguardian.com/world/2018/jan/28/fitness-tracking-app-gives-away-location-of-secret-us-army-bases" rel="nofollow">https://www.theguardian.com/world/2018/jan/28/fitness-tracki...</a><p>I haven't used it, but if the company is so set on opt-out versus opt-in, maybe it'd be preferable to default to 1st or 2nd degree connections only for location sharing. For the fly-By functionality where it's supposed to be public, it seems a little reckless to disclose name, picture, and location by default. I can also definitely think of other popular apps that do this.