Automaticly lock threads over a month old

this idea isn't in the rejected board

No. The definition of a necropost is a post in a thread where the last reply was really long ago, and it does not contribute to the previous discussion of the thread.

While in theory, yes, this may help to prevent stupid unreasonable necros, you never know. I've seen it pretty often already that a thread was necro'd and brought back really nicely, so that discussion could actually start again. Also, "accidental" necros don't happen too often anymore with guest posting (to my knowledge) being disabled in all boards but forum support.

So, that's a no from me.