I've had a couple of Warner DVD titles go bad also -- when I enquired about a replacement I was informed they wouldn't be prepared to ship new copies to me here in the UK (even if I paid for shipping!).
I had the same bad feeling when I opened up Julius Caesar. It's been some years since I viewed it and the whole reflective side of the disc had blotches all over. It worked fine and no hang ups though. Curiously, Air Force and Dark Passage look mint and froze up.
Checked two more films: Air Force & Baby Doll - both played fine.
Also checked two Warners discs from 2005, The Americanization of Emily & A Face in the Crowd and they were both fine.
The problems I had with Julius Caesar were the single disc edition not the one that was part of the Marlon Brando boxset.