If there are extenuating circumstances behind a downward trend in grades (e.g., an illness or family crisis), these should be explained to the college in writing by the student and supported in writing by the school counselor. The college will probably be sympathetic and stand by their original acceptance. I have heard of a few cases when a college put a student on academic probation at the start of the freshman year.
Colleges may also revoke acceptances if the student is suspended from school or arrested outside of school. Again, because the college does not want to do this, the case will be carefully evaluated and the outcome will most likely depend on the nature of the infraction and the circumstances surrounding it.
Finally, if a college should discover that an applicant was dishonest on his or her application, they may well rescind the offer of admission.
Best wishes for the New Year and may all your admission news be good news!
Elizabeth LaScala Ph.D. guides college, transfer and graduate school applicants through the complex world of admissions. She helps students choose majors and programs of interest, develops best match college lists, offers personalized essay coaching, and tools and strategies to help students tackle each step of the admissions process with confidence and success. Elizabeth helps students from all backgrounds to maximize scholarship opportunities and financial aid awards. Visit Call (925) 891-4491 or email at firstname.lastname@example.org