14.1 Assessing a Snooker in baulk (rule E) 

All positions for the cue ball in baulk must be examined. This includes being able to place the cue ball in the jaws of a pocket (but not touching a ball 'on'), or being able to place the cue ball in the middle of a cluster of balls. A Referee should not attempt to place the cue ball into such positions; the fact that it could be done is enough to deny a snooker. 

14.2 Nomination of free ball (rule P) 

Consider the following: A player is on yellows, and has been awarded a foul snooker. The player nominates a ball by pointing at a group of red and yellow balls. While the Referee is trying to figure out which ball was nominated the player gets down and plays a shot at that group of balls that results in the cue ball hitting a red ball on the first impact. 

In this situation the player should have waited for the Referee to confirm the nomination, by pointing to the nominated ball. The player has committed a standard foul.