I don't know that this topic is controvertial in itself, but because it does happen in the controvertial section, it seems to make sense to leave it here.

Moderators are here to help keep threads on topic. Granted, we (at least I) sometimes violate this principle when the thread drifts slowly in other direction.

You can try the gentle/humorous approach and post something like Help! The thread is being hijacked? Who can save me? Who can bring it back on course? I don't know what the topic was in your other forum, or just how off-topic her comment was, or how you phrased your letter to her, so I can't comment on her reaction.

But if that happens here, you can contact a moderator, who can step in with a more offical voice. Completely off-topic responses can be deleted, or even split off into their own thread.

Paris is lovely in the spring.

Okay, this is hypothetical, of course, but if a thread is locked, it's locked for a reason. People who continue to post to it by posting on whatever thread is nearby stand a very good chance of having that post deleted.

That's different from the idea of a thread drifting into other territories.

Generally, I think confrontations between members is something to be avoided - I would definitely privately ask a mod for help if it happened, and I would expect either a warning from the mod in the thread or for the post to be deleted.

But that's only my opinion. As a moderator, I'm interesting in hearing what other people think should happen in a situation like that.

If I came across something like that in the EF, I would probably delete the post. If the locked thread was locked because it had become too bulky, perhaprs I'd suggest that the girl started another thread with a similar topic. But to post in the closest thread just because the other one was locked is kind of ill-mannered to me.

By the by, I don't see any harm in bulky threads: it means that a subject is interesting for people. Why to deprive them of talking on that? Even if it's such a single-post thread as "Change one letter" that we have in the Word Games section here. (Well, it gets on my nerves sometimes, I must confess, because now it mostly goes in circles, but I try to handle it and let people play! )

Edit:

Anon, why don't you register here?