Funny you mention that. I had to get special permission to use my HP-15C on a "calculators allowed" exam in a first-year "calculus for non majors" course, and had to show the instructor how to reset its memory.

Which I found amusing, because the list of approved calulators included several graphing calculator models with computer algebra systems in ROM sufficient to produce correct answers to every problem on the exam, and they're worried about what I might have stored in the memory of a (then) 15-year old keystroke programmable calculator with a single line, ten digit, seven segment numeric display.