As much as many don’t like it, it’s textbook trespassing. It was private property, if they ask you to leave and you don’t you can get arrested. And cops love to pile on with obstruction and resisting arrest charges. I’m an advocate of protest and speech but if you want to plan to not be arrested, you have to be on the public easement or some other established public property/forum. I think here they were planning to be arrested, and I respect that.