Why does an incomplete order do not get canceled automatically?

If I'm not mistaken I know somebody posted that incomplete orders after two weeks, if not started, will be cancelled automatically. I tried searching the post about this but can't seem to find it. I have some incomplete orders from 3 months ago sitting in my active list. I'm not inclined to nudge the buyer because I think they ordered by mistake.

My second question is if the incomplete order automatically gets cancelled, will this add up to my cancellation ratio?

I would appreciate answers on this, or if somebody can point me the link to similar discussion that would be great.

Thanks in advance :)