Why don't charities all join a lottery system?

So I was thinking today about the hundreds of charities and how they can have a lottery system that gives them money directly on via stamps. Kind of like the publisher clearing house. Instead of posting stamps for magazines, you pick up to 5 stamps of charities you would like to support, and the pot that usually goes to the states, gets put into the charities.

At the end of the year you can hold onto your tickets as evidence of the amount you paid for your tickets. So if you bought 30 dollars worth of tickets each month you get 360 dollars charitable deduction. The main pot going to the winner can be as small as 250,000. People get to give to several charities, and there is a chance they win something and the charities don’t have to hire solicitors and people don’t have to be harassed at home by phone or mail. Also corrupt charities become a thing of the past. Only legit charities can enter the lotto.