[Tagging] Roundtrip and closed loop in relations

[Peter Elderson]

> 
> If following the route marking you will get back to start... It's a circular route.
> As previously stated you could find marking on both directions and be a single line straight and then reverse.
> With old wiki definition this is Roundtrip=no... Now it is Roundtrip=yes
> Seems sane to me.

A linear walking route marked in both directions is not a roundtrip. You're not guided to turn around at the end and return to the start. You are free to do that and make your cross-the-alps trail a roundtrip, of course, but I have yet to encounter anyone who does that. Could become an Australian hype maybe? :)
So no, I wouldn't expect linear walking routes to get tagged as roundtrip=yes. circular is fine too, as long as it can be applied to routes that are not strictly circular (closed_loop). Such as having a common approach/exit section, crossing itself one or more times, or having a common middle section between two loops. This would still qualify as roundtrip to me, because the 'service' i.e. the waymarking, brings you back to the start.  bidirectional waymarking does not a roundtrip make, it just says you can choose to do the hike in both directions.
At the same time, if circular just means the same as roundtrip (for walking routes), I would not change current tagging. Lots of work to achieve nothing, not my favorite.