Void sticker on NBA Jam GG Cartridge?

A few weeks ago I bought a copy of NBA Jam for Game Gear that was boxed. However, after I'd bought it I noticed it had a huge great big void sticker across it - identical to the security seal on the box.

Does anyone have any idea why it's like this?
Probably so that if some kid decides to take the thing apart and breaks it, Sega can claim he voided the warranty and is not obliged to replace it. Essentially useless by now, since I don't think Sega is into supporting warranty claims for Game Gear games anymore...