How do admissions officers keep tabs on admitted students?

What do I need to make sure to do not to get rescinded? Are rescinds very rare?

For starters, the HS is required to send in a final transcript.

Don’t get a D, don’t get arrested, don’t be found to have lied on your application. Other than that, it is very rare to get rescinded.

@skieurope Is it necessary for me to directly inform the college of updates on my ECs? (I’m not quitting) or will someone do that for me as well?

No, it’s not necessary.

Risk of rescission tends to come from the college seeing any of the following on your final high school transcript, particularly if not informed about them before:

  1. Earning a D or F grade in an in-progress course.
  2. Grades or GPA in in-progress courses show a substantial drop (some colleges specify a GPA threshold while others have more vague wording).
  3. Dropping or changing in-progress courses.

As stated above, basically don’t get into legal or school disciplinary trouble and don’t get significantly lower grades than you had when you were accepted.

Also: At Harvard and some other schools, students set up what they thought were private chat groups or Facebook pages. Then they shared racist, sexist, and otherwise obnoxious memes. I think about 40 students got rescinded.