Ultimate has an important difference with most other sports.
It has a code of conduct written into the rules...they call it the 'Spirit of the Game'.

Spirit of the Game: Ultimate stresses sportsmanship and fair play. Competitive play is encouraged, but never at the expense of respect between players, adherence to the rules, and the basic joy of play.

Accordingly, it is appropriate that the spectators have a similar code of conduct on the sideline. Here's my suggested draft:

Spirit of the Sideline: The Ultimate sideline stresses encouragement and support. Cheering is encouraged, but never at the expense of respect for all players and fans.