USPS Missing Disk/Never Delivered..

Firstly, I'd like to say Hi and that I'm a new member, just started renting... I'm just another movie enthusiast that loves watching movies, Theater/Home especially in 3D and I used to rent from Blockbuster, Hollywood Video and of course Netflix back in the DVD days, I was a long time customer and I still use Netflix. I always looked forward to getting the movie discs in the mail.. I don't recall ever not getting an expected disk though. I rented my first two Blu-ray 3D movies, I got one and the other is MIA unfortunately. I already returned the one but had to report the other missing, 3d Blu-ray Rental is aware of it and will send another thankfully. Here's my [question and concern] "This should be a thread" btw... I live in Philadelphia so big busy city, how come the mail in disk sleeve have the name of the movie printed on them? I think the disk sleeve should be more discreet and not advertise what's in it and If it's a new popular tittle it might just pull a Houdini. So what happens now? What if the second replacement grow legs and go awol? I understand I won't be charged extra and the replacement is not going to be part of my actual subscription count but this can't keep happening with USPS right? Is this normal?