The following rule is probably violated more than any other of the fifteen class rules. The reason being that most of the skippers and hardly any of the crew members even know that this is a part of the rules. However this is a situation that can bring on a protest from another competitor.
The correct position for a crew member while racing with the intent to keep all the weight to the high side is to sit with the back to the cabin with the legs hanging over the side of the boat. This is permissible because the torso is well inside the vertical extension of the sheer. Boats with lifelines do a pretty good job keeping crew members inside the vertical extension of the sheer, but without lifelines there is no restriction to remind the crew that they are hiking beyond the limits of the rule. A good way to remember “is the body of the crew or the skipper in the boat or out of the boat”.