### Please describe the problem.

When running the assistant, it seems to want to drop all files in the worktree from my NAS which is in the transfer group. This fails because of numcopies thankfully but it strikes me as very odd and potentially dangerous for it to do this when it knows that it can't drop these files.

It also unnecessarily spams the logs.

### What steps will reproduce the problem?

```
git annex assistant --stop
git annex assistant
```

### What version of git-annex are you using? On what operating system?

```
git-annex version: 8.20210428
build flags: Assistant Webapp Pairing Inotify DBus DesktopNotify TorrentParser MagicMime Feeds Testsuite S3 WebDAV
dependency versions: aws-0.22 bloomfilter-2.0.1.0 cryptonite-0.28 DAV-1.3.4 feed-1.3.2.0 ghc-8.10.4 http-client-0.6.4.1 persistent-sqlite-2.11.1.0 torrent-10000.1.1 uuid-1.3.14 yesod-1.6.1.1
key/value backends: SHA256E SHA256 SHA512E SHA512 SHA224E SHA224 SHA384E SHA384 SHA3_256E SHA3_256 SHA3_512E SHA3_512 SHA3_224E SHA3_224 SHA3_384E SHA3_384 SKEIN256E SKEIN256 SKEIN512E SKEIN512 BLAKE2B256E BLAKE2B256 BLAKE2B512E BLAKE2B512 BLAKE2B160E BLAKE2B160 BLAKE2B224E BLAKE2B224 BLAKE2B384E BLAKE2B384 BLAKE2BP512E BLAKE2BP512 BLAKE2S256E BLAKE2S256 BLAKE2S160E BLAKE2S160 BLAKE2S224E BLAKE2S224 BLAKE2SP256E BLAKE2SP256 BLAKE2SP224E BLAKE2SP224 SHA1E SHA1 MD5E MD5 WORM URL X*
remote types: git gcrypt p2p S3 bup directory rsync web bittorrent webdav adb tahoe glacier ddar git-lfs httpalso borg hook external
operating system: linux x86_64
supported repository versions: 8
upgrade supported from repository versions: 0 1 2 3 4 5 6 7
local repository version: 8
```

https://github.com/Atemu/nixpkgs/tree/498831397e77a265c240cf8f8a7d15e738f2f05b


### Please provide any additional information below.

The log is full of

[[!format sh """
# If you can, paste a complete transcript of the problem occurring here.
# If the problem is with the git-annex assistant, paste in .git/annex/daemon.log
drop SOTERIA path/to/file (unsafe) 
  Could only verify the existence of 1 out of 2 necessary copies

  Maybe add some of these git remotes (git remote add ...):
  	d7d728f7-891a-4035-a758-c7ee80a8017a -- MB-<redacted>

  (Use --force to override this check, or adjust numcopies.)
failed
# End of transcript or log.
"""]]



### Have you had any luck using git-annex before? (Sometimes we get tired of reading bug reports all day and a lil' positive end note does wonders)


> notabug per my comment; [[done]] --[[Joey]]
