[TomMarius]

The venue is not yours. The owner (and thus the performer) sets the rules. If they want you to come in pink clothes, they have every right to not let you in if you're not entirely clothed in pink.

On the other hand, you have every right to not go to the event.

I also don't like these phone pouches for many reasons. As I said earlier under this post, Eddie Vedder also forbids phones. He'll just stop doing whatever is he doing and wait until everyone puts it away. And that's his right, your statement that he can't do it because the phone is yours is wrong.