You should still tell them you had a problem, it might actually be the disc. They have people who make disks jump through hoops. If they didn't have anything to do they'd get fired.
Based on the upsurge of bad discs, I suspect that they've eliminated or cut back on the disc checkers in favor of waiting for customers to report defective discs. But they don't have a selection for reporting "This disc played fine in my 4-year-old player but not in my 5-year-old player.
My theory is that they aren't buying as many new discs so the percentage of bad disks is going up.
Couple ideas that rehash what other people have said.
If you can update the firmware on your player, try it.
Try blowing out dust with some canned air.
It may be the one player is just a little more sensitive than the other and the disc was just on that cusp.
Might just be a fluke, you need some reproducbility to really know.
Side note, always try washing the disc with a little soapy water. I thought this idea was crazy when it was suggested to me, but it works more often than not.