One of the ways I've seen botnets skirt this problem is by using cartoon profile pictures. Cartoon bots don't work quite as well on Facebook as they do on Twitter and Instagram (where they're only used to inflate favorite/follower stats, not to sell stuff). Unfortunately, it's probably hard to convince someone to hail a Lyft if "social proof" is coming from someone with a cartoon face.
With that said, these bot puppeteers could feasibly get around identity theft/copyright/social proof issues by using CC0 stock photography sites. There's plenty of free photos out there for people to use, i.e. as profile pictures.
Not that it'd be any more ethical, but at least it would be legal.