If you actually expressed offense to what he billed you (which was a loss for him), I promise you, you’ll be at the bottom of his priority list moving forward.

So I would advise that you learn a bit about better tenant screening; in PA, the state now has free internet searches for lots of important things pertaining to tenant screening, including criminal court records, landlord tenant magistrate records, and even traffic driving offense court records (useful for the tenant that drives for the first job or is Uber or Lyft driver on the side).

Personally, I find it really offensive and think you need another hobby.

Is there a way (legally) to prove he is smoking in-unit (other than logging the offenses)?  

In fact as I type this now I find it a bit offensive that was even said.  

You nicely bug the owner, the owner starts bugging the PM, and eventually the tenant will be gone.But, I think I might go on the offense as far as calling the cops if the tenant is coming onto the property and being vocal. 

No offense, but you couldn't simply google this and research yourself  before you made this thread?

No offense, but this isn't because you are a "nice guy".

LolNo offense, but your analogy is a logical fallacy.

Soon, in NYC, collecting rent will be a punishable offense.