not reading too much into it. If a competitor has both plugs and muffs on, and he removes the muffs during a COF, in essence he isn't removing his hearing protection. True it would cause confusion, but I would think he'd win in arbitration, unless there is a specific rule that addresses extra hearing protection and it's removal.
However if the worry is about a competitive advantage, why does it only apply during a COF, why not for the whole day? if you start wearing them, you have to finish the day with them, no swapping out as the COF designs call for. I think perhaps the rule should be more clearly written to avoid any arbitrations on the matter. it would be a simple rewrite.