What would happen if someone tattooed formulas on their arm

What would proctors do in a situation like this?
One time in high school, this kid wrote formulas down in permanent marker on his hand. Him being the genius that he is was showing off his neat idea to his friends and the teacher saw and made him tape up his hand with duct tape for the exam. I thought it was pretty funny but doubt it would be handled this lightly for the mcat