[just another ref]

Originally Posted by Snaqwells

You can ask all the rhetorical questions you want, Socrates, but the fact remains 99.999% of officials, including those with ties to the rules committee, that we've talked to agree that when the case play says "call," it means "signal."

In most cases this is true. But is this not also more or less universally accepted:

While one official may not overrule another official's call, he may share information with that official which may convince him to change his own call.