I know plenty of guys who spend large sums of money to save ounces on their boats, like buying titanium bolts to swap out for stainless,etc. .You are going to have a hard time convincing these people to carry an "extra"life jacket ...
If their need to "save ounces" outweighs their need to obey the law and follow the rules, then nothing I say will convince them. I trust that none of us here fall into that group. Does anybody here honestly believe that they have to break the law in order to win a race?
Believe it!:
This competitor opened up his already ligthweight Zhik (CE Approved) jacket and removed more "bulk" floation, re-stitching with the white thread. Point was to make it less wind draggy...not so much to make it lighter. This was at a US National Tornado event. There were others at the event doing similar alterations.