Astyanax
The situation in this topic was a person being trespassed because he had a business that made and sold T-shirts over twenty years ago that other people wore.
Since the guy didn’t and never had shown up at the venue wearing or displaying such apparel, your scenario is irrelevant to this topic.
As mentioned previously, trespassing the guy on those pretenses is a snowflake move by butt hurt managers who just wanted to retaliate against him for allowing his business - over twenty years ago - to sell T-shirts with messages they disagreed with.
This is a different set of case facts from Pruneyard v. Robins, where the individuals had actually engaged in activities on the plaintiff’s property.
However, the Pruneyard v. Robins decision does indicate that the guy tresspassed from MSG could prevail in a lawsuit, since his alleged violation was one where he never engaged in activities on or near MSG’s premises at any time.