On hole #3 at Cherokee Hills, Player A was preparing for his second shot just to the left of the fairway. In taking a practice swing, Player A accidentally made contact with his ball, causing it to come to rest in a fairway bunker:

Was the practice swing considered a “stroke”? The answer is no… the Definition of Stroke states: The forward movement of the club made to strike the ball. But a stroke has not been made if the player accidentally strikes the ball when making a practice swing or while preparing to make a stroke (amongst others).
So does Player A now have to play his ball from the bunker? The good news is no, because Rule 9.4a states: If the player causes [their ball at rest] to move, the ball must be replaced on its original spot (which if not known must be estimated). It is important to note that the ball in this case must be replaced—not dropped.
Did Player A incur a penalty? Unlike when a similar situation occurs with a ball in play on the Green, there is a consequence in this instance. Since Player A’s ball was at rest in the General Area, USGA Rule 9.4b governs: If the player causes [their ball at rest] to move, the player gets one penalty stroke. None of the five exceptions to this Rule would apply to this circumstance, so Player A was assessed one penalty stroke.
Player A then asked whether the ruling would be the same if he had accidentally caused his ball to move on the Teeing Area. In that case, the ball on the Teeing Area would not be “in play” until after the player took his first stroke, according to Rule 6.2b(5): When starting a hole or playing again from the teeing area under a Rule, the ball is not in play until the player makes a stroke at it. If a teed ball falls off the tee or is knocked off the tee by the player before the player has made a stroke at it, it may be re-teed anywhere in the teeing area without penalty.
So if you’re going to make an “Oops”, make sure it’s on the Teeing Area or the Green!