High school kids asking for money for delivering Sunday newspaper

They give this whole speech about how the subscription will help pay for their education or something. One time I gave a kid $20 and he never delivered any newspapers. Since then two other kids have knocked on my door with the same gig (one came tonight and said he was born in Afghanistan). I told them that I didn't want any newspapers and just gave them $10 each and wished them good luck. I didn't ask for a receipt or anything, so if they spent the money at McDonald's, I wouldn't know. Not that I care...it's only ten bucks and I know high school kids can sure use some extra money now and then.

Question: Is this a scam or is this some sort of a legit high school program? Also why do they always come on a Friday night?