If you are even thinking of playing that game you should just apply EA to both. MIT could defer you to RD (so you would still have a chance). You could find yourself committed to UC, wondering, “What if?” and tempted not to pull the MIT app as agreed. At that point your guidance counselor will back UC because you indeed committed to ED, and the integrity of the high school is at stake (putting at risk acceptances both for other students who are applying there this year and for future students who will apply).