Well it depends on the circumstance I guess, since a federal building is public property then it is open to protest, now if a group tried to occupy a private business or residence they would be trespassing, if no consent from the property owner.
Well, yes, I 100% agree that you cannot enter a private business or someone's home to protest, unless given permission. I think the law is quite clear on that. If you do, then you deserve all the consequences that come to you.
I found this:
http://www.firstamendmentcenter.org/faq/frequently-asked-questions-assemblyIn sum, there is no unfettered right to protest on government property. Protests must be peaceable, and the government has the right to impose content-neutral, reasonable time, place and manner restrictions on expression.
Furthermore, as the Supreme Court said in Kokinda, “the government’s ownership of property does not automatically open that property to the public.”
The government has greater power to regulate expression when it acts as a proprietor controlling its internal operations than it does as a sovereign lawmaker.
This means that government officials could limit protests inside a courthouse because the government has important operations to conduct. It must be able to control its operations to carry out its functions. The government must be able to carry on its own speech and expression free from interference. Contrast this with the public sidewalks two blocks from a courthouse. Here, the government cannot argue that it is conducting its own internal operations. Speech restrictions there would implicate a forum analysis and trigger a higher degree of judicial scrutiny.
The second point was already established between us, since a protest cannot interfere with the functioning of an individual.