Question: How likely is it that a school will waitlist or reject a student because he/she is overqualified and probably would go to a more prestigious school, so the school would "save" its acceptances for another candidate?
Waitlisting seemingly overqualified applicants is a factor at some colleges, but being able to pinpoint which ones in particular participate in that ploy is very difficult. One school that has been relatively famous for this in recent years is Washington University in Saint Louis (WUSTL). WUSTL likes to see a sincere expression of interest from its applicants.
The obvious way to express the "proper" level of interest is to visit the college, interview, express that interest in some fashion within the application (showing that you know something about the school, its programs and resources, and how they apply to your needs), and perhaps making contact with your regional admissions representative during the application evaluation period.
Since it is impossible to tell whether this is a trend in Tier 2 colleges that don't want to waste time with students who are using them as a back-up or a legitimate tool for managing enrollment, your best bet is to continue to follow our advice, found throughout our site's special stories and features on issues like Early Decision, Wait Lists, and so forth. Use our site's search engine to find the information you need.
You apply to colleges you want to go to, putting your best foot forward. This means preparing well in advance, building your academic and co-curricular portfolio to reflect both your accomplishments and the values the college or university upholds.
You can't possibly know whether you are overqualified or not, since that term is rather vague, and nobody really knows what specific variables a college admissions staff is looking for in any given year or for any given program they are recruiting for. It's difficult to be overqualified on an individual basis, but certainly quite easy to be underqualified and underprepared.
Apply to the schools you want to get in to, prepare well, and focus on getting in, not "playing the game." Leave that to the colleges that are having difficulty shaping their enrollment. You can get a sense if this practice is prevalent by asking other students, parents, and guidance counselors what their experiences have been.
If you are seemingly overqualified for the particular school you want to attend, then you must take steps (such as those above) to prove your "honorable" intentions. Otherwise, you may be viewed as just another applicant looking for a safety school, although safeties are becoming more and more elusive thanks to the rising level of overall competitiveness.