Its def for cheating. You can find examples of replaced ingredients lists, products labels, barcodes, and people writing on the inside peel of oranges and other fruit on reddit and other places.
What would you write on a cheat sheet for the SAT? Equations for volume of a sphere or something? I don't remember there being anything that required memorizing, and since you could bring a graphing calculator there would have been no need to write things down anywhere else.