Possible reason that today was chosen is that it is the midpoint date from the original Camp David summit back in 1978. That summit ran from 09/05 - 09/17. This is pure speculation on my part and I am assuming that this is due to terrorist attacks originating from the middle East.
They might of just done it today because the President wasn't in DC. and that the "terrorist committee" is in LA and wouldn't be able to come back in time to stop it. God Bless that my dad is alright as he is trapped in DC. My uncle, dad's best friend, works at the WTC but had today off as his father in law died yesterday. RIP all the people who died in this tragedy.
An emergency worker in New York noted, ironically, that the date today is 9/11 - sounds like 911, the emergency number. Don't know if that has any significance.
Isn't it also the 1 year anniversary of the escalation of conflict in the middle east? I might be wrong.