Gets jus' a lil' cramped in there doesn't it? Hard to roll over at night, eh? :scratch:
Seriously, many sweeps won't allow the use of a PO Box. There are folks who'd use multiple email addresses in conjunction with multiple PO Boxes to enter a sweep multiple times (cheating) in order to gain an advantage. Needless to say, sweeps promoters don't much care for that.
Some sweeps will let you use a PO Box for a mailing address, but you still must list a physical residence address.
Interestingly, you can be homeless and still enter sweeps if you use a laptop and a wifi at Starbucks. 'Course you'd still need an address. Either a PO Box Box (catch 22), or a friends address.