Because normally they don't have plenty of stock?Just popped out to my local electrical retailer in my lunch hour and walked out 10 minutes later with a 32GB Black iPad.
They had plenty of stock, not sure why the fuss about pre-orders.
Yup, don't think its fully charged but its like 80% at leastcant wait to get home and use my first apple, is it charged for use out of the box?