App Store: submitting app with future release date then changing it to earlier date after it is approved

Lets say I submit my app for approval now. I set Availability Date to something like Nov. 30, 2011, because I have not yet decided when I really want to release my app. Then fortunately, my app gets approved.

1. Will I be able to edit the Availability Date after my app is approved?
2. Assuming question 1 gets a yes, let's say I then edit the Availability Date to Dec. 3, 2010. Will my app be available on the App Store on Dec. 3, 2010? I've heard that setting it to a future date after it was already available will take it out of the store, I want to know if the reverse also works.
3. Will there be any drawbacks for doing this? (This is actually my main concern)

For the record, I did search for similar questions, but still not satisfied with the replies in the other posts. Thanks in advance!