A few years ago, a 777 CA (I think it was a UAL CA) slipped and fell down the jetway stairs either before or after doing a walkaround. He later died from his injuries (lots of head trauma IIRC). I consider those stairs to be a bigger risk than walking around the aircraft and decided things were better off if I just load the MCDU and let one of those young, spry FOs go up/down those stairs and do the walkaround. Besides, their eyesight's better than mine and they can probably spot abnormalities quicker/better than I can.