Patrick Johnson said:
There isn't prolonged contact. As I said above, high speed video has confirmed that. Bob Jewett, who has had a leading role in revising the rules, was also an organizer of the high speed video research project (The Jacksonville Project) I'm talking about.
Prolonged contact??? I think that's a different question.
The Jacksonville Project proved that hitting through a frozen ball doesn't result in an automatic double hit of the cue ball.
One slight distinction that is being a bit overlooked is: that experiment never said that it's "impossible" for there to be a double hit. It basically just says that a double hit isn't naturally going to occur. It would take some additional influence in order for there to be a double hit.
For example, a cue ball frozen to an object ball, which is a short distance away from another object ball. Thus, you could get a legal hit on the cue ball, and as the cue stick separates from the object ball, the other ball (short distance away) is impacted causing a second hit on the cue ball via chain reaction.
The current interpretation of the rule basically throws everything else out the window. Because the cue ball is frozen to the object ball, the shooter has a license to hit it however they want. This is because that initial hit will be legal, and any such resultant actions, might require a physics degree and maybe even a good camera in order to diagnose, so therefore ignore it and rule in favor of the shooter.
Trick Shot example: There's 1 trickshot which is actually a cheat, where there's a cue ball, an interference ball, and the true object ball, such that the cue ball and object ball are in line to a pocket, but the interference ball is right inbetween the other two with basically a halfball hit. The trickshot artist shoots the shot and knocks in the object ball. But, the object ball was never hit with the cue ball, instead the trick shot artist strokes his stick through the contact with the cue ball, and continues his stroke until the cue stick hits the object ball.
Now back on topic: If you have a cue ball frozen to an object ball and a cluster (large or small, maybe even a single ball) on the other side a short distance away. The shooter can swing away through it all, and it is very difficult to tell if everything happened cleanly or if the shooter stroked through and fouled as an after-effect of the initial clean hit.
Patrick Johnson said:
I do have another objection to the rule as-is, though - I think a legal shot should require that the CB impact an OB, defined as coming into contact after being separated during the same shot. For consistency, then, I suppose this should also be the definition of a "hit", so that merely moving a frozen OB without coming back into contact with it would not qualify as a hit.
I can see your point on that one. Makes for a simple resolution.