Interesting... I noticed a couple years ago that if I put the DVD in the return envelope backwards (and the bar code couldn't be seen thru the little window) it took longer to mark those movies as returned (I'd get the email at 3, 4, 5 PM instead of 7 or 8 AM) and it often led to an extra day of waiting. I now take care to always have them in the right.
You haven't noticed any extra delay by doubling them up?
Did you read the article about the Netflix processing center? There isn't any automation on the envelope side, rather there are teams of people opening them up and pulling the discs and the sleeves.
I think the barcode window is entirely for outgoing routing.
I did read the article, but I didn't see where it said that there was no automation on the receiving end. Maybe I missed it, it was a long article.
When I noticed this for myself, 2007 sometime, I had a common problem where every Nth disc would take an extra day to be received, and that would really throw off my pattern, which mostly was just to have a couple movies for the weekend.
So soon hypothesized that it'd happen on days the barcode was not visible. So to test, I put 1 of them wrong intentionally, mailed all 3 at the same time, and the 1 that was wrong did indeed take an extra day to be marked as returned.
So I didn't have any real facts, just an observation that seemed plausible to me.
No, I have not noticed an extra delay by doubling up two discs in one envelope.
Usually the mail delivery between the local Netflix center and my address is overnight both ways, but occasionally it takes two days for an envelope I return to be processed. I've attributed that delay to the post office, however, and not to having two DVDs in the same envelope.
You haven't noticed any extra delay by doubling them up?