Well, outside of the pacemakers (because people a heart condition could be at risk when riding a coaster regardless) there ARE life-saving electronic medical devices that people use.
My insulin pump, for one. There's nothing about my diabetes that precludes me from riding a coaster, but the insulin pump theoretically COULD be interfered with by strong magnetic fields.
However, the fields presented by LIMs, brakes, etc., are NOT a hazard. At least, they haven't caused me any problems yet :) (I've been on Pittfall at Kennywood, Chiller at SFGAdv)
I'll be on MF, and don't expect any problems. I'll check the pump when I get off just to be SURE, though ;-)
--Greg
*** This post was edited by GregLeg1 on 3/29/2000. ***