American national anthem at WSOP main event???

[Masquerade]

I'm about two months too late with this post, but is it really true that the Main Event of the World Series of Poker was started with a singing of the American national anthem?

It seems incredibly inappropriate for a supposedly international event (World != America) whatever country it's held in. And how did non-US participants react?

I don't like to go to other countries and behave in a manner to cause offence so I probably would've quietly slipped outside. But how +EV and tilt-inducing would it be to simply ignore everyone standing up singing and mutter anti-American slogans?