Why the line on some SNES Catridges?

[Hobie-wan]

Late to the party, but there's even more than that. The earlier revisions of the regular SNES have the locking mechanism in them. The later versions of the regular (or at least some of them) that have the little warning sticker on top and the revised board inside simply leave out the lever that slit into place with the power switch. So there's no lock on top of the later carts now having the old notch.