Two questions please...

[WetWired]

I'd suspect that they found those threads by searching, rather than by scanning through page after page of threads.

This might be more effective:
This is a private mod I use to prevent thread digging; ignore the "Member" and "Senior Member" stuff, that ties in with my activity mod, but it should work fine without if you use the "Junior Member" setting for all users. Threads can still get dug up by mods and sticky threads are exempt.

This is not a release. This mod comes as is, with no support.