I would not say it's a scam. I will say it's not transparent enough exactly how much is collected and what it's used for.
If you want a chance to win it's fine. If you actually want your money used for a charitable purpose I suggest a more transparent organization.
The sad part to me is many non-profits use the lack of transparency to hide shady operations so they are all under a cloud of suspicion. Look at the recent Red Cross scandals. Ask Tim Arnold why he no longer works with the Salvation Army.