Bug#848186: piuparts: "FAIL: Package purging left files on system" for files under /srv might not be a bug

[Adrian Bunk]

Source: piuparts
Severity: normal

Currently the testing migration of proftpd-dfsg is blocked by the
following piuparts error (counted as "regression" since the package
is not currently in testing):

https://piuparts.debian.org/sid/fail/proftpd-basic_1.3.5b-1.log

0m32.6s ERROR: FAIL: Package purging left files on system:
  /srv/ftp/      not owned
  /srv/ftp/welcome.msg   not owned

0m32.6s ERROR: FAIL: Installation and purging test.
0m32.9s DEBUG: Starting command: ['umount', '/srv/piuparts.debian.org/tmp/tmpVdZtzA/dev/shm']


/usr/share/doc/debian-policy/fhs/fhs-2.3.txt.gz says:

/srv contains site-specific data which is served by this system.
....
    The methodology used to name subdirectories of /srv is unspecified as there
    is currently no consensus on how this should be done. One method for
    structuring data under /srv is by protocol, eg. ftp, rsync, www, and cvs.
....
    Distributions must take care not to remove locally placed files in these
    directories without administrator permission.


I'd tend to say that not removing the file on purge is correct,
but the whole situation looks rather underspecified.

Is there any rationale why not removing files under /srv would
without a doubt be considered a bug?
If not, please don't flag this as an error.

Thanks