DracoSuave
First Post
It's certainly true that Shades can use cover granted by their allies to hide. I also vaguely recall the ruling that you're talking about, though I can't seem to find where it might be located.
This too is included with every printing of the Stealth rules ever.
Most questions involving stealth are actually explicitly addressed within that rule set. It seems long and complex, but 99% of all questions are answered directly in there.
There's not a lot of 'rulings' to be made. It's not a 'ruling' that you can't use allies for cover... the rules say explicitly you cannot. It's not a 'ruling' that you can't make a stealth roll to become hidden during the same action you stop being hidden, it's explicitly written in the rules.