So far you talked about US vs CE PFD and the fact that the CE ones are more comfortable. Fine. When I was in the US I was using a US PFD and yes, it was bulky and uncomfortable. I see the point of using a CE one for around the buoys racing. As long as it is tolerated by the "class culture", fine. Not that I care, being in Europe...

But I would protest in a heartbeat a competitor wearing a modified PFD. Not because I would gain an advantage in doing so, but because as safety coxwain at my sailing club I am aware that a properly fitted PFD can save lives. And I would hate to see a slippery slope where all competitors start modifying their PFDs because "this other guy did it". I would not give a damn about "class culture" in that case.