Not to confuse the issue, but I just posted that language to answer the question of how to make safety rules "optional" within SIs.
HCA does NOT make any attempt to change PFD requirements, or any other class rule changes. If you read the SI template, you will see that the safety section is really about check-ins, etc.
I HAVE seen language added to cut down on "safety protests" at lots of other regattas, and while I really don't like it on a personal level, it can help to alleviate what some consider to be "frivilous" protests (for class rules requiring paddles, whistles, etc.).
Personally, I don't think individual events should mess with class rules. That's just part of growing up with the militant SMOD Hobie rules, I guess.
I also feel farily strongly that we should just follow the local laws, which is what USSA is saying in their RX. I don't want to debate CE vs. USCG, but it's always dangerous for an OA to attempt to sidestep USSA or worse, local laws.