clarification

This question furthers the hot topic of whisker pole use in racing. Though I have a fairly extensive sailing library, I am embarassed to admit I don't have a copy of the racing rules. Today the question arose as to whether the inboard end of a whisker pole must be attached to the mast, or...

Some clubs allow the use of a whisker pole on the same side as the boom in racing, others consider this taboo. What is the currently generally accepted practice, and is there any interesting history attached to any changes that have been made concering this issue?