Don't potential motion blur issues override the need for SR? In other words, don't you need a semi-fast shutter speed anyway? Or do you get lucky and the motion is stopped often enough?
Also, I'd have trouble using the K20D if I also had a K-x. Unless of course the lighting is really bright, in which case I'm not sure why you need the SR. But on the K20D I suppose you still might, because of the weaker high ISO performance.
In any case, give it a try if you like. I'd feel uncomfortable having SR active while I moved the camera around abruptly.
Obviously a tripod is your best bet when feasible. And if taking photos is your only responsibility, hopefully you can simply concentrate on the task and be ready most of the time (granted, execution is often harder than theory, but we seem to manage somehow).
Last edited by DSims; 03-12-2014 at 04:29 PM.