As a retired college professor, a point of law is shared with all college professors in the USA, whether they remember it or not. The USA - Americans with Disabilities Act educational component says students must declare their disability to the school's disability support services or not be eligible for accommodation. For example, if a college has a rule about "no eating in a classroom" and a diabetic starts hypo in the middle of a quiz and needs to eat, if they are not on the school's disability list, then they must leave the quiz to treat their "undeclared" hypo and accept whatever academic penalty the course syllabus lists. If they have declared to the school's disability office, then they can eat at their seat and continue on the quiz. If the faculty member does not enforce the syllabus, there is room to argue academic favoritism. This is NOT FAIR in my eyes but it is the way many schools look at disabilities - declared = real, undeclared = does not exist.
So, my two cents worth is - if you are a student, declare your diabetes to your disability office and review the accommodations your are seeking like: eat in class when no eating rules apply, testing BG during class - step into hall or perform at seat, have pump that beeps and not be "penalized" for not silencing a communications device, and similar events.
Bottom line, always discuss so you have as much protection to defend from college faculty who may be so far into their subject matter they forget how to be human and compassionate.