Snooker Rules

[anaxcrosswords]

Something that's confused me a little bit as I thought I understood the rules of snooker. During this year's World Champs I've seen several instances where a player - snookered or otherwise - has fouled by missing the object ball, but has not been asked to play the shot again, even in situations where the result of the miss leaves nothing at all for the opponent.
In fact I've just seen it in the Bingham/O'Sullivan match where Ronnie applied a touch too much swerve and missed his escape while on the final red. The result was cue ball/object ball separaste by just about the full length of the table, with Bingham presented with very little chance of a pot but needed the last red (plus black) and clearance to tie.
Why didn't he just make O'Sullivan play again? It looked liked the obvious thing to do, but to me it looked like both players knew the shot wouldn't have to be taken again.

[Jascon]

Maybe the Rocket made an honest attempt mate, and just missed it

[FredPuli43]

The commentator said that it would be very unwise to ask O'Sullivan to take the shot again, the suggestion being that he would get it right next time , leaving a far more difficult shot for the opponent.