if the only person who's gonna serve as "back-up" for that proofer is the post-processor, that puts too much stress on the post-processor. that's exactly what d.p. has done, and that's why they have so few volunteers for that task...
Agreed that PP at DP is stressful, in part because of the high standards expected there of PPs -- don't see how one can meet their expectations without at least doing a SR pass oneself, which supposedly isn't required. But to me a more fundamental part of the problem is that it is relatively easy to start a book at DP and then expect someone else to fix the "problems" at the other end, leading a PP to stare at a potential PP book and say "why in g--- name would someone have started this book project in the first place???" Again, its pretty easy to find a book project where one can pretty easily predict it will be read 1000 times more than some other book. Which one would you rather PP? A book that gets read 1000 a year, or a book that gets read 1 time a year? If one can "solo" a compelling book myself, or "PP" a drab book at DP, which would you choose? The other problem is if you PP a book you haven't lived with through the entire process then you "start from scratch" with your knowledge of the book, its author, its proofing problems, etc, and getting up to speed IMHO is almost as painful as doing the whole project "solo" in the first place. Don't get me wrong, I *love* the feeling of having others proof one's choice of books at DP and say "wow, this is a really cool book to be proofing!"