I looked into founding a company in this space and steered straight back out of it because yes, by far and away the VAST majority of demand in the market of study tools for high/middle schoolers is cheating. Below that, parents are involved and there's a market there (but a bad one, because of double sales where you have to sell through the parent to the child even though those two actors have misaligned incentives).
That is interesting and kind of what I suspected anecdotally. I think it's unfortunate for people who aren't aware of all this. That is what I will say.
A cheat sheet could be a piece of paper you're allowed to bring to an exam. To make a proper cheat sheet you have to understand the material you're working with anyway so it usually doesn't help you.