1. Do schools care eabout what other schools you're applying to? I know most schools don't ask but say someone accidentally lets it slip. For example, if Dartmouth finds out Applicant B is also applying to Harvard and Amherst, will the admission officer's mind immediately jump to "she just wants a highly ranked college," which isn't the case. Obviously, the higher ranked colleges have lots to offer.
2. Do colleges care that a recommender shares a recommendation with an applicant? Is that illegal? I can easily see a college not wanting to admit someone who disregards the law, so let's say this is also slipped.
3. If something must be mailed in, and it says it must be "by this date," does that mean that I have to give it to the Post Office before that date, on that date is also acceptable, or that it has to be received by that date?