400 Bad request

[coviex]

Funny thing is there are two sibling threads on the forum named
identically and answers to my question wind up here.
http://forum.nginx.org/read.php?2,2757
http://forum.nginx.org/read.php?2,215184
And I didn't know about that so sorry for asking twice.

I get that requests with %% are invalid.
But why they don't appear in logs?
Can I show pretty 404 page for those 400?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,2757,215210#msg-215210