General rules question

[Bob Jewett]

Except the rules say a different OB or the CB must hit a rail, ostensibly because it is part of the rail

That's not the way the WSR are written. They say that some ball must be driven to a rail after the cue ball hits an object ball. They also say that a ball that is frozen to a cushion is not considered to be driven to that rail unless it leaves the rail and returns.

 

[ideologist]

That's not the way the WSR are written. They say that some ball must be driven to a rail after the cue ball hits an object ball. They also say that a ball that is frozen to a cushion is not considered to be driven to that rail unless it leaves the rail and returns.

Sorry, I was remembering whatever nonsense league rules.

So the original question appears to hinge on having a referee or someone declaring the frozen ball as "frozen"

 

[Bob Jewett]

... So the original question appears to hinge on having a referee or someone declaring the frozen ball as "frozen"

Yes. The OP didn't specify whether the frozen call had been made before the shot.

If there is no referee, the seated player will normally call the ball frozen and if the shooter objects they can inspect the ball together. Some shooters will call the ball frozen on their own (a frozen ball is to the shooter's disadvantage).

The rules did not have an explicit "player must be notified of a frozen ball" clause until 1977 and it was worded unclearly when it did appear.