It's called Tufts Syndrome with Tufts and WashU routinely decline over qualified applicants in order to boost yield. It's also called Ivy Leagure Reject Schools. Don't fooled by WashU's weekly invitation to apply. WashU will reject both under and over qualified applicants.
http://talk.collegeconfidential.com/tufts-university/72457-tufts-syndrome.html