The context is often "Can someone buy themselves into a better college by paying for test prep?"

But yes. If only because of the time constraints of the test (and it's more than that), sitting down and taking the SAT cold would be really hard for most people without prior exposure to similar tests. Heck, I'm pretty sure I couldn't today. I'm guessing I would do pretty well on verbal but too much of the math would be way too far in the past. And I wouldn't have time to derive formulae even if I remembered enough first principles to do so.