As a fellow short person I think this is an interesting question that doesn't get much press. According to Steve Dashew in his exhaustive report on heavy weather(
dashew heavy weather ) there can be a
danger of the
pfd slipping off of the shorter person while being either airlifted to
safety or dragged back on board. I suppose that means if might slid over ones
head just floating or being dragged by a tether. The right thing to do apparently is to wear leg straps. Somehow I doubt many people do that. I wonder if there are smaller PFDs on the market?