I get that all the time - I also get it with people that I did actually ride with, though. As far as I can tell it just looks at the route all both took and the approximate time and makes you BFFs, even if your unknown associate is loads faster / slower than you and you didn't actually see them once during the ride.
It knew, for e.g, that I did the same Maths Geek ride as mountaingoatmatt, even though I left a full hour before he did, and even though he got to the destination something like 3 hours before I pootled up.
I get that all the time - I also get it with people that I did actually ride with, though. As far as I can tell it just looks at the route all both took and the approximate time and makes you BFFs, even if your unknown associate is loads faster / slower than you and you didn't actually see them once during the ride.
It knew, for e.g, that I did the same Maths Geek ride as mountaingoatmatt, even though I left a full hour before he did, and even though he got to the destination something like 3 hours before I pootled up.