Back when I was still on Twitter, I remember folks in the office were having a game to see who had the most bots following them. I guess there was some online form that evaluated the people following you and determined if they were real or not.
I'm sure bots have gotten much better at avoiding detection, but it would be interesting to see if these programs could still ferret them out as real or fake. Likewise, to your point, it would be interesting if the users themselves could tell either.