15 degrees is alot! When you take off on a commercial airplane, you are at an angle of about 3 degrees & we all know how that feels when you try to lean forward.
I agree with the above poster's idea. Maybe the instructions on what to do when the ship tilts should be included in Muster drills. Even if passengers don't give it a second thought, at least instinctively you'll react to what you learn. Human mind is amazing under duress.