So you’re making the assumption the other guy is lying?That's a loaded question. If they are smoking "dope", I'm gonna assume it's Weed and not hard drugs. There has to be context.
I've met dudes who are choirboys, but I wouldn't piss on them if they were on fire. I've met dudes who were shrubs and I'd give them my last dollar.
That said, if the only qual was they had the same skillset and one smokes weed and the other doesn't (My question is how do I know that because that's presumed confidential), I'd take the dude who smoked...because he's honest by telling me he smokes weed.