xfs_metadump of frozen fs?

[Eric Sandeen <sandeen@xxxxxxxxxx>]

xfs_metadump(8)                                                xfs_metadump(8)

...
       xfs_metadump should only be used to copy unmounted filesystems,  
read-only
       mounted  filesystems,  or  frozen filesystems (see xfs_freeze(8)).  
Other-
       wise, the generated dump could be inconsistent or corrupt.
...

However, it doesn't work on a frozen fs.  There's no way to programatically
detect a frozen fs AFAIK...

Has this ever worked?  I see 3 potential solutions:

1) a --force option to proceed even if mounted
2) teach xfs_metadump to optionally freeze a mounted fs and proceed
3) fix the manpage

Thoughts?

Thanks,
-Eric