<p>They don't care. H has the best yield in the country. They don't worry about where else students apply to. They even tell alum interviewers not to ask about other applications.</p>
<p>The exception is if you apply ED. Harvard will not accept anyone who has an ED admission. If H finds out that it has accidentally accepted such a student, it will withdraw its acceptance. That's because by applying ED, the student has promised to attend that college if accepted.</p>