hmm intersting. How do they know you did not start before Nov 1?
Honor principle. I have started at midnight on the 1st both years now - there's a psychological boost.
It's a lot of fun. There's no time to edit, so you just focus on writing the story. If you get to 50,000 and aren't done, you keep writing. If you only write 10,000, well, that's more than you've have done otherwise!
For me, it's a great exercise.