Apparently David Zeuthen committed a patch back in February (appears in udisks2 >= 2.0.91, afik) that lets you single-point (or selectively) switch Udisks2 back to the nice, sane, predictable “Removable drives mount to /media” behavior instead of the asinine “Drives are owned by some user who happens to be logged in at a local session at the time they are plugged, mounted to /run/media/$USER/$LABEL, and ACL’d to that user” nonsense that has been a near-constant source of inconvenience lately. I’m surprised it took me this long to find it.
Following these instructions, all you have to do is create a Udev rule (ie. /etc/udev/rules.d/99-correct-media-mount-point.rules) with the line ENV{ID_FS_USAGE}=="filesystem|other|crypto", ENV{UDISKS_FILESYSTEM_SHARED}="1", and storage mounts to /media/$LABEL (You may want to leave out crypto, it actually makes sense for encrypted volumes to be obscured from other users like that) with no funky ACLs by default.
No more tedious user,noauto,nofail fstab entries on all my machines, for all my frequently-used discs to prevent that behavior! Hurrah!
