That might be true. If 500.000 people block every big street in a city, you will read the signs and think about the cause. What a protest can afford depends on

That might be true. If 500.000 people block every big street in a city, you will read the signs and think about the cause. What a protest can afford depends on how many are protesting. Going to the specific event in question, the convention of Activision Blizzard, if one person tries to blocks the event with protest, they will be removed, if necessary by physical force. If sufficiently many block the event with protest, the protest will be successful.