As far as the effect of the label drying, it was the biggest problem for CDs. CD surface/label layer is the data layer. If you damage it, or write on it with pencil or rip it off with a label, that’s your data you’re removing.
Fair enough, what I encountered at work quite likely was a burned CD rather than a DVD. I didn’t realize though that DVD is less susceptible to data loss from label side damage, that’s interesting to know, and I’ll certainly be looking into that more.
Yeah. On CDs the label is the data. On DVDs, the data layer is fairly safely sandwiched between two halves of the thick plastic layer. And for BDs, it’s extremely close to the surface opposite the label. I.e., most of the plastic is in between the data and the label. So any scratch that makes it through is likely to cause major damage to the data instead of just affecting readability (which can be fixed by resurfacing a CD). That’s why BDs have a scratch resistant coating.