I always wondered about the intelligence of people who participate in these...
First of all, you have to realize that the money comes from somewhere....
Second of all, if people are going to be sending these random addresses money, wherever it says in the letter to send them, why would you leave other people's addresses? I'd replace the address with my own, and send the letter out.
Also, no one "checks" to see if you sent money. Why not just mail out the retarded letter without sending money?
In closing, it fully irritates me on how simple and retarded this scam is. Seriously. If I want to send out 6 million chain letters... why should I pay for the right?