Todd, that MAY save you from getting a ticket, although you can still be cited if the PFD isn't "readily accessible," but always carefully check the SIs on this issue: US SAILING frequently requires the USCG PFD be "worn" and not just "carried."
Um-kay... Get the bright orange USCG pfd, fold it in half and velcro it to your boom... right about where you'd bonk your head in a chinese gybe situation.
Take care of two issues simultaneously - an approved vest in an "readily accessable" location AND not getting your brains knocked out by the boom...
Now, if you attach 50' of 3mm spectra to that pfd, does it also qualify as "throwable"?