If you could automatically enroll yourself in every sweepstakes legal for your locale, then you could also offer that service to anyone else interested. People could pay you 5 dollars a month to get automatically entered into every sweepstakes.
Of course, this scales badly. The more people who take your service the less valuable it will be as the odds of winning will decrease. Perhaps the natural balancing point would be somewhere where you could still profit. Might be best to charge nothing but take a cut of the winnings. That way people wouldn't be discouraged from joining by the diminishing likelihood of winning, and the chances that someone from your pool would win would only increase over time.
Like with plenty of such ideas, the answer is to do it anyway - scale it until it breaks, making sure you're always making profit yourself, and then call it a day. Enjoy your money and do something else. A while later people will forget, and someone else will do the same thing.
(The real answer is, of course, to not do this at all, because it's unethical. But that consideration doesn't stop everyone, unfortunately.)
Of course, this scales badly. The more people who take your service the less valuable it will be as the odds of winning will decrease. Perhaps the natural balancing point would be somewhere where you could still profit. Might be best to charge nothing but take a cut of the winnings. That way people wouldn't be discouraged from joining by the diminishing likelihood of winning, and the chances that someone from your pool would win would only increase over time.