I'm fairly sure that the Invisible Man Legacy set I had was OK when I bought it - as routine I use a PC based disc checker that reads every sector on a DVD and checksums it to make sure it's OK when these discs are involved. But I got the same set out after reading this thread and found that...
Not much chance of this happening with the Legacy sets, because most of the films in those were originally on single discs. I had all of them, and kept them because of the crappiness of the DVD-18's in the Legacy versions. A shame because the Legacy sets were nicely packaged, took up less room...