huh, okay I always wondered what the button did. I always assumed it was to 'activate' codes that were input, maybe for a different game that I hadnt played yet and thus hadn't needed to use it yet.
Incidentally, Game genie and Gameshark were the first time I realized I was committing piracy (or any crime), when I was asked to leave a store for writing down a code that was in one of those 10,000 Game Codes books. It's been a long sordid tale of hidden algebra notecards and microscopic formula sheets ever since.
This life of crime chose me.