When the time expires, bonding resin on the DVD reacts with the air around it, making the DVD unreadable. I wonder... If you leave one of these in your player, will it leave resin byproduct gunk in the disc tray, on the laser emitter, etc.?
I'd never buy one anyhow.
My understanding is that the reaction turns the plastic of the disk dark so the data on it can no longer be read, it doesn't turn to goo.