Starwood Preferred Guest - Disappearing $199 Rate at W SF

Last night (Apr. 6), I saw a great rate of $199/night at the W San Fran for the week of Oct. 25. I don't know why, but I didn't book it right then. Now, the rate has disappeared. Anyone else see this rate?

Late October is HUGE conference time in SF. Its possible someone went and booked a huge room block, leaving only rack rate rooms left . . .

Happens all the time to both the W, Westin, and LC in SF. What I noticed is that (usually) once it's gone, it's gone! I normally book really far in advance to secure good rates.