Is the batsman out if a) he deflects the ball away from his wicket after playing it. i.e. with bat, foot etc to avoid being 'played on' b) if he, when out of his crease, 'accidentally' stopped the ball hitting his wicket by interposing any part of his body on the ball's flight path? The logistics to me is similar to an lbw decision.
Note: Updated to reflect changes brought in on Oct 1 2017 which removes Rule 33 Handling the Ball, and merges with Law 37 - Obstructing the field
According to the rules of cricket
37.1.2 The striker is out Obstructing the field if, except in the circumstances of 37.2, in the act of receiving a ball delivered by the bowler, he/she wilfully strikes the ball with a hand not holding the bat. This will apply whether it is the first strike or a second or subsequent strike. The act of receiving the ball shall extend both to playing at the ball and to striking the ball more than once in defence of his/her wicket.
Exceptions to the above is primarily around not being out if it was to avoid injury.
The striker is out LBW in the circumstances set out below. (a) The bowler delivers a ball, not being a No ball, and (b) the ball, if it is not intercepted full pitch, pitches in line between wicket and wicket or on the off side of the striker’s wicket, and (c) the ball not having previously touched his bat, the striker intercepts the ball, either full pitch or after pitching, with any part of his person, and (d) the point of impact, even if above the level of the bails, either (i) is between wicket and wicket, or (ii) if the striker has made no genuine attempt to play the ball with his bat, is either between wicket and wicket or outside the line of the off stump. and (e) but for the interception, the ball would have hit the wicket.
Interception is defined as...
(a) In assessing points (c), (d) and (e) in 1 above, only the first interception is to be considered. (b) In assessing point (e) in 1 above, it is to be assumed that the path of the ball before interception would have continued after interception, irrespective of whether the ball might have pitched subsequently or not.
So with all the above, LBW is considered at the point of first strike of the body without the bat. If that is not LBW, he is only given out if he swipes at the ball to prevent the ball touching the wicket with his hand unless it is to avoid injury.
Using the bat to prevent the ball striking the wickets after the shot has been played (and already made contact with either the body or bat) is considered not out. If any other part of the body including and it is deliberate then it should be out.
I have seen this happen in matches and have not seen anyone given out
Great answer from aqwert there. I'd add that Law 33 deals with handling the ball as an act of playing it, including protecting the wickets. The question asked (likely in error - I think aqwert's answer was spot on) about contact after playing it, in which case Law 37 - Out Obstructing the Field, may be relevant. Law 37 notes in part:
Either batsman is out Obstructing the field if he wilfully attempts to obstruct or distract the fielding side by word or action. In particular, but not solely, it shall be regarded as obstruction and either batsman will be out Obstructing the field if while the ball is in play and after the striker has completed the act of playing the ball, as defined in Law 33.1, he wilfully strikes the ball with
(i) a hand not holding the bat, unless this is in order to avoid injury. See also Law 33.2 (Not out Handled the ball).
(ii) any other part of his person or with his bat. See also Law 34 (Hit the ball twice).
That, of course, was the controversial fate of Ben Stokes recently.