I guess it is because the term "9/11" has become an understood shorthand worldwide, as it were.
For what it's worth, at that time I was in the desert, and jogging home that evening in the dark (?) I saw an owl swoop down from a window in a derelict building. I took that to be some sort of omen, as it was the only owl I ever saw in Saudi Arabia.
Spooky? weird? ... or just that it's a better idea to jog in daylight? But (as many will recall) it gets dark early (not to mention suddenly) out in those parts.
