What's the scenario for rescuing a capsized drift boat? Do drift boaters not wear PFD's because they suppose the chance of a capsize is so slim?
Since I have a very hard time imagining rescuing a kayak without a PFD, and a very easy time imagining it capsizing, I ALWAYS wear a PFD. Ditto for rafts.
Here's Pit Boss' recommendation: if you think it looks stupid or sissy wearying a PFD, do what I do and attach a Rambo-ish looking
river knife to the front, handle down. The knife will look cool and might even someday have a chance to save your life, though PFD's chances of doing so are much better.