honestly, that particular rule predates the guy you're probably thinking of. It actually goes all the way back to when a Chinese vendor was having a slap-fight with a guy who claimed he'd been sent a hot-pack, and the two of them started inviting each other to fly to China or the US, respectively, to have a fistfight.
I've seen multiple vendors do it since, and what it mostly tells me is that this dude is way too emotional and short-sighted for me to be comfortable sending him crypto and hoping he'll sell me drugs responsibly. (I say dude because I've never seen a woman do it except Tracy, who is somewhere on a beach with a lot of people's money looking at tits and also a dude so case in point, really).
