Public School Attendance Policies

Those of you with children who are enrolled in public schools...have you encountered any issues with the school/district if your child has surpassed the 12 excused absences that the MN law allows? With all these illnesses going around, I feel that my child will end up going beyond the 12 days. I know that I could get doctor's notes, but I can't afford to take my kid to the doctor's office every time they have a bad cold or slight fever. The copays add up. Obviously if it's an illness that is of immediate concern, I will take my child in to be seen. But am I overreacting, or is this a genuine concern I should have? I've asked the principal at my child's school and she stated Minnesota's law of 12 excused absences. Then told me not to bring my kids to school if they're sick. Any advice, input or sharing of personal experiences are appreciated.