800 points on one section will get you into MIT, as that's a perfect score. 1000 on combined seems very unlikely to get you into SAT; the 25th percentile is 1500.
I was replying to a comment indicating that URMs can get in with extremely low scores. My point is that they can get in with somewhat lower scores. But they still have to clear a much higher threshold than 800 combined.
I believe it doesn't disincentivize blind guessing. It just counteracts it. If you can eliminate one answer you should guess. Even if you can't eliminate an answer you break even.
1: https://en.wikipedia.org/wiki/SAT