There's a part in the documentary where they're interviewing the record label owner and when they ask him about it he immediately flips out and ends the interview.
I dunno about that, every time Sugar man or I Wonder started playing when I was growing up, someone would tell me "This guy isn't famous anywhere else! No-one even knows where he is!". I must have been told this factoid 20 times when I was a teenager.
You forgot to mention the "click on this one specific checkbox or your source code is now leaked to the entire internet forever" part. So actually, not that simple and potentially much much worse.
Tax rates on the rich are at historically low levels. Rich people would still get UBI but the top level tax rate would effectively cancel it out (and more). Current welfare wastes a lot of money on admin/staff/fraud investigations and none of that would be needed with UBI since everyone gets it.
People would still want money. UBI isn't going to be enough for a lavish lifestyle, people will still want to work. It would make lower-paying activities like art/open source more viable though.