🚀 go-pugleaf

In the forum that I most frequently frequent (I think I could have expressed that better...) it happens pretty rarely - and as often as not it's a deliberate action by the originator of the thread, thinking that if he/she posts in several places a reply will be more likely.

As you say, if it can be caught in time, deletion of duplicates is the simple answer - if not, cross-referencing and locking is necessary. I can't think of a feasible way of automating that process after the event, although I know some forum software prevents more than one post being made within a certain time limit to help reduce accidental double-posts to a single thread (which is perhaps a different issue).