Except that Skaven don't use any of the "normal" warmachines. (meaning things like cannons, stone throwers, and bolt throwers)
So it doesn't make much sense to make that kind of blanket rule 'known' in a new army book.
Yes there are still people that think it's going to be in the BRB (and others are hoping like mad for it). But until we have the new book in front of us, it's purely speculation either way.