In our league, there are divisions with similar playing time requirements. Failure to abide by the rule results in a forfeit and can result in a disbarment of the coach from the league. I don't know what the protocol is with respect to the officials versus the table personnel, who are hired by the league, but this creep should be hit hard! With regard to a "T", I would think whatever rules cover illegal substitutions, bench personnel on the court, and unsportsmanlike conduct ought to provide plenty of ammunition.
JCurrie's suggestion to have the fan quietly mention it to the other coach seems reasonable, however, depending on the situatation that might be deemed insighting a riot
. In any case, it also should be reported to the the table as they are the ones normally charged with enforcing compliance with playing time requirements.