I've seen some of the work by Jenna Bouma (Slowerblack, East River Tattoo in NYC), and you can tell that it's hand made. The reason for this is that the lines are made by a bunch of dots connected rather than a single motion. Even at her speed, which quite frankly is really impressive, it's a slower technique. Less skilled usually results in a more obvious dotted line.
As for any possible "pros", it's a different feeling than machine tattoos... And people on tumblr will love you...
I'd say that chances are that this stick and poke "artist" has most likely never been an apprentice, and probably doesn't have any training in keeping a safe workplace other than what they learned from the internet and common sense. I mean you don't have to be an expert at the internet to find some pretty sketchy "artists" on instagram.