Agree on the above. The rules say when it should be called frozen, but do not indicate a persistence of such state past one shot, therefore, to be frozen, clearly it must be called frozen once prior to the shot about to be taken, not carry over from a prior shot or inning.
It's a legal opportunity to interrupt the shooter, study balls near the rails, then call out frozen or not, time after time, allegedly in the service of just getting it right.
If Earl did that, stand up and walk to the table and interrupt his opponent to check frozen balls prior to every stroke, we would all be up in arms, and call him crazy.
Wait, we do that anyway.