Upvoted cause you're apparently the only mod that saw it worth their time to give a reply.

Mods should obviously, as a rule, own up to whatever they moderate. I've seen many a forum go down in flames because of "invisible modding". You almost can't blame them, it's human nature that great power wielded anonymously will end up being abused.

So, the obvious solution is to fix the software to display "edited by ..." whenever someone edits something. I say "fix", because it's almost a bug. All popular forum software has this feature, and there are almost no good reasons not to enable it.

Failing that, mods can easily start taking this matter in their own hands by simply adopting the habit of appending a short tag to whatever got edited, for instance {ani} in your case (or soemthing like that).