Imo, anyone who sets up a dope deal with someone they don't know, especially through the mail, is nutz.
Maybe it's a cop; maybe it's legit.
But the biggest danger is that you send the guy your $$$, and you never get squat.
I knew a guy--we'll call him Mr. B, who would cruise mj sites, and when he saw a post of someone complaining about finding weed, he'd PM them and offer to sell them some.
He didn't have any to sell.
If the person wanted a sample, he's buy a gram somewhere and send it to them.
They would send him $$ for a large amt., and Mr. B would tell them he never got it.
That's the problem with deals by mail. The dealer sends the weed first, the buyer doesn't send any cash, or more than likely the buyer sends $$ to the dealer and gets nothing in return.
What's the buyer gonna do, call the cops?