Betas are run separately for different regions. "If you're in, you're in" applies to all beta phases in your home region."
So people with the US or Asian beta won't be able to participate in the european one.
Shortly after, this was tweeted:
There was a beta scheduled to begin 11 Sep for the EU region but it has been delayed one week. NA will continue soon, but no firm date yet."
So at least US psn won't have to wait long. (Awwww yeah!)