Unfortunately that absolutely correct- we are all accountable for our actions.
As an extreme, if Sid brought in a large child doll, dressed in a Sunderland shirt, hanging from a small makeshift scaffold and waved that in front of Sunderland fans you think he would not have some level of accountability for any public disorder which followed in the ground.
The level of intellect used to bring a Newcastle shirt into the ground when playing Sunderland defies logic to me and created a significant internal stadium security event for the last 15 minutes of the match (albeit it wasn't Sid, this time, who actually waved the shirt in their faces).
Whether it is a stadium ban- thats for the club. But someone needs to have a word with this 35 year old man and stop him acting like an embarrassment and more like an adult
And, as I've said elsewhere, "icons" come and go- "Tango" has been banned by Wednesday for two seasons for swearing at a steward. Sid has already been banned from Lincoln United and Lincoln City (for 3 seasons) previously. Seems some people don't learn do they.