How much dissent should we allow?

[whistleblowerusa]

Forgive my late response, I have only just joined.
In my experience, which goes all the way to pro level and college, dissent is different at every level. Your own tolerance must be the fine line between what is considered dissent or not. At national camp we always say "use the 3 P's", Public, Persistant, and Personal. When it hits all three of these Ps then it's probably time to show a card.
During play we hear many things, sometimes it is just frustration, sometimes it's the coaching, sometimes it's the spectators. If a player says something and leaves then it could work better for you to allow it. The player vents and then cools down. When the player chases you or stands in front of you and shouts or comments loudly, then that is clearly dissent. Sometimes carding a player can also make things worse for you. Use your "soccer sense" and game managment skills to handle these situations. Remember the 3 P's!