The question arrises, "What about the people who are already left handed?" To this we simply answer, everyone slips up sooner or later regardless if they are southpaws or not. We have seen MULTITUDES of lefties buffaloed over the years for various reasons and the enjoyment in their defeat never gets old!
Your chapter can use any rules you wish as long as it is consistent for the members. We choose to make a hard line in the sand so everyone is on the same page from the start.