<p>That likely won’t work. EA is negated the moment you get accepted ED, because ED is binding. There is no threat that you won’t attend CMU in favor of this other school. </p>
<p>Colleges have been known to blacklist students in the past, which is a big reason of why breaking your ED contract is a Very Bad Idea. If you say, “Hey CMU, Stanford gave me this great EA offer and I can’t attend ED because you didn’t give me enough money,” CMU could very easily say “Oh no you don’t” and call up Stanford and tell them you just broke your ED contract. It could be a common myth, but people often claim that a school will drop a student applicant for something like that. After all, they have many thousands of students to fill your place.</p>
<p>Additionally, saying ‘I can’t attend unless you match something like this offer’ is bargaining, fritzy. That’s exactly what people do to bargain for more aid. :p</p>