It's not BS, people have known about The Warden for ages now, it has even been implemented in D2 and they busted maphackers with it. It definately isn't BS.

EDIT: Err, as for it reading the titles of windows, that is probably BS. As far as I know, all The Warden does is scans what DLLs are injected into the game's memory and then checks a list of bad DLLs then sends a report back to Blizzard that says whether you have bad DLLs running or not.