With the chance of qualifying for the play-offs still alive, Boro hope Saturday's game against Stoke City was not their last at the Riverside this season, but it saw a child go onto the field during the match and he and his father, who filmed the incident on his mobile phone, have been banned from the ground for life.
Entering the field is a criminal offence but what compounded the matter was the threatening and abusive behaviour of the father when the pair were asked to leave the stadium once the child had returned to his seat.
A club statement said the incident "trivialised the importance of the game to our fans, town, players and management."
The club have "encouraged" the police to face further action.
Boro have also identified four children who came onto the pitch after the game, and have said their parents also face banning orders from the Riverside.
"Entering the pitch while the game is in progress will not be tolerated," stressed a club statement.
"Abusive and threatening behaviour to our staff will not be tolerated.
"To enter the pitch at any time is a criminal offence as is abusive and threatening behaviour."
It is hard to imagine any of those incidents being anything less than well-meaning but they set a dangerous precedent.
Pitch invasions are traditionally not unusual after the final game of the season but there were ugly scenes on Saturday when Gillingham and Rotherham United supporters invaded the Priestfield Stadium pitch.
Some Rotherham fans entered the playing area after Richard Wood scored what they thought was the clinching goal only for it to be disallowed, and then when Georgie Kelly actually did. Smokebombs were thrown on both occasions too.
But there was a much bigger incursion as soon as the final whistle blew, confirming the Millers' place in next season's Championship. Gillingham fans, angry at their club's relegation, also ran on and punches, plastic bottles and other items were thrown between the rival supporters with policing and stewarding inadequate to prevent the trouble.
The refusal of both sets of supporters to leave the pitch meant Rotherham were unable to celebrate on the field with their fans until an hour after full-time although when they did it was extremely good-natured.
Earlier in the season two Rotherham fans ran onto the pitch as Accrington Stanley's Harry Pell prepared to take a crucial penalty, with one of them barging into him. Both were arrested and given life bans from the New York Stadium.