http://twitchviews.co.uk/ Post the twitch video url there, it automagically gets unmuted for you to watch, which means the muting is made clientside...
Sometimes i'ts also based off of countries - like certain bands/songs/companies ban you from listening to their music if you live in certain countries or are posting a certain country's music 'outside' of that country.... If a company or group of people don't have a problem with it then it wouldn't be auto-muted ... so it would have to be an issue with UMG and record companies, moreover.
