It may be the OP wants to know if conveying that he or she turned down Cal Tech regardless of whether that happened) in favor of applying to MIT would convince MIT that OP was worthy of an acceptance. But I’m sure MIT has faith in its ability to choose students and doesn’t let information about how other schools feel about a candidate influence their choices.
I think MIT choices the candidates they believe to have the best fit to MIT. They have been at the business of selecting students for a good long time. Given their 2 year return rate and their overall graduation rate, as well as the success of their graduates, it appears that they don’t need input from other schools and they especially don’t need input from other schools through the report of the student.
Had the crop of students currently at MIT not gotten into MIT, most would be happily pursuing study at other universities. That is the kind of student they select.