I'm sorry to hear that there will be no way to distinguish the new DVDs. Several members of fitness forums have already exchanged their DVDs with other members, not realizing they were defective, nor that replacements were forthcoming.
I realize that there are many bootleggers on eBay. I'm careful who I buy from there. But now I won't even be able to trust that my trusted sellers have the improved copies, since there's no way to tell unless played.
And on the flip side, I can only hope that I will forever be able to use my DVDs, because if I choose to sell them down the line, their quality will always be questioned.
Diane