It goes back to my story on how the touring aspect works in the Nightwish thread. As far as the club is concerned, this is a *confirmed* show . They confirmed with the booking agent, no one else. A busy venue such as BB King's isn't going to give you the date based on a "possiblity" or a "maybe." Symphony X's booking agent did his job and got them the date.
By not stating anything in public, this gives the band the opportunity to cancel the show if ncessary and not look bad to the public because they never "confirmed" the show. It's how politics work in the touring industry now with clubs going early with dates.