This utility can erase the NOR on the EZ Flash 3-in-1. I cannot confirm that it works with other NOR-based Slot-2 cards. If you erase as little as 4 blocks, your DS will no longer show a GBA Game in Slot-2.
Ah, yes, portrait mode, surely the best way to film a row of people. If only there were some way to fit a wider shot, at the expense of height... if only...