Let’s say a student who was accepted into a college with a 3.0 gpa has a contingency in the admissions packet which states he “must not suffer a significant drop in GPA”. What would be a significant drop from a 3.0?
Without knowing the school in question, a D or F will almost certainly result in the acceptance being rescinded. A string of C’s will likely not do him/her any favors either.
Having said that, the vast majority of people that ask a question in this vein here are concerned whether their 0.05 drop in GPA will result is a recission - it won’t. Just don’t let senioritis get the better of you.