Processing stops upon reaching read-write snapshot

I have noticed that the last 60 or so of my `btrbk` snapshots are read-write, and therefore can't be sent with `btrfs send`.

I'm currently in a position where the btrfs filesystem containing the snapshots has a minor error and will only mount RO, meaning that I can't change the snapshots to RO, to be able to `btrfs send` or `btrbk archive` them to a new, error-free filesystem.

I determine the ro/rw status via:

# btrfs property get -ts /path/to/subvol
ro=false

Would it be worth checking that the above command returns `true`?