This is video of a head coach in an indoor football league running out onto the field to push down a player from the opposing team, after that player had scored a touchdown.

Dave Brumagen, head coach of the Lincoln Haymakers, of the Midwest based Champions Professional Indoor Football League, runs onto the field and pushes down a player from the Omaha Beef, after that player scored on the Haymakers.

I don't know the back-story on this, but it would be hard to imagine many scenarios where as coaches' actions, such as this, are justified.