USC is one of the most applied to schools in the entire country right now, and at every admissions event I’ve ever been to the admissions staff has talked about how demonstrated interest IS taken into account. Every school wants to enroll students who want to be there. That much should be common sense, and it isn’t just shown through campus visits ($$$) or signing up for a mailing list but also through the essays that students write talking about why they want to go to a specific school and enroll in a specific program.
To the extent that students with numbers beyond USC’s normal stats are rejected, it can also be because students are scattergunning applications to schools that they have no interest in beyond the school’s U.S. News ranking. Admissions officers read a LOT of essays and have VERY good B.S. detectors about these things.