If you're really good or make money for people (take Lady Gaga as an example) you can get away with anything. But most people or the people that that post is directed to aren't.
As a side note I always wondered why back in the day Bill Gates, when he was the richest man in the world (or near that) always wore a suit to business meetings. I mean you would think he would just do whatever he wanted to. But apparently he still had to answer to "someone" and felt it wasn't appropriate.