The Celtics and Nets will play Game 6 Friday night in Boston and there will be as much going on off the court as on it. This rivalry is hot in both places.

After Game 4 in Boston, the Nets’ Jason Kidd was furious at the comments directed at him and his wife by Boston fans. Kidd felt fans had “crossed the line” from what they have a right to express and what becomes too personal.

Back in 2001, Kidd went through a wife abuse charge that ultimately saw the charges dropped and anger management action taken by Kidd to deal with the problem. Celtic fans raised those unpleasant times Monday.

Kidd’s wife Joumana and their 3-year-old son were at the game in the seats. Celtic fans stood in front of them during the game with “wife beater” written on their backs. Throughout the game fans yelled the same at Kidd.

Joumana said there was a lot more invective voiced by the fans around her, most of it not repeatable. “I don’t want to give specifics because it will encourage more ignorant people and drunks to say things.”

She continued, “That was the most hateful crowd I’ve ever seen.”

Kidd said he was worried for his family’s safety. The Celtics’ Paul Pierce said after the game when told of the taunts, “That’s the way the playoffs are.”

Abusive language and actions directed at opposing players, and sometimes even at home players, is not new in sports. Always there is the question of where to draw the line and when home team officials should step in to stop such activities.

Families of opposing teams tend to be seated together at visiting arenas and home fans are aware of that fact. Taunting of spouses goes on in every sport from time to time, especially in the postseasons.

One solution is to put families in suites away from the crowd, but there are not enough suites in most sports facilities to do that. Another course is for the families to stay away from the road games, but that is giving in to the “ignorant people.”

Joumana did find help in the stands from some Celtic fans so put off by what was going on that they tried to quiet the situation, but without much success. That is a dangerous setting in itself and portends fights in the seats among fans.

Kidd says his wife and son will be at the FleetCenter for Friday’s game. He did not say where they would sit. Celtic officials have an obligation to be sure fans do not cross the line again.

Hateful remarks directed at players will go on, but when they are directed at family members in the seats, it would seem that the line has been breached. Teams in all sports are grappling with where to draw the line in these “fan rights” cases and there are no easy answers.

What’s sad is that the issue has become more pressing because there seem to be more “ignorant fans” at events and the invectiveness of their actions grows harsher and more unseemly.

Better the line drawing be done in earnest now than wait for a serious incident where someone is hurt in the seats. Then everyone will look back to see that hindsight is still 20/20 and someone should have acted sooner.

Old Town native Gary Thorne is an ESPN and NBC sportscaster.