Why was he buying coals from you instead of from a head shop or whatever?
Are you sure it's just him that was the idiot?
No offense meant, but I'm not sure you've thought your assessment of this event through as well as you could have.
What's the likelihood of you crossing paths with this individual again?
'Cause if he's got the typical junkie swiss-cheese memory, and he hangs out in your area, I see a surprise chokeslam in this guy's future.