2. Yes, I imagine this is either to avoid suspicion or because the person writing/pasting this comment wasn’t paying attention and chose the wrong rating. Even fake reviews will have an error rate above 0 :-)
3. I was curious about that too. Another possibility is that the service really does suck, that’s reflected in the old negative comments, and eventually these businesses resorted to paying for reviews. All guesses though.
The alternative explanation is: they're real people who are terrible with technology and the internet. I've run a site where people could rate their experience with others, and the correlation between stars and text was only so-so. Lots of people considered 1 to be best, even though clicking on 1 showed a text "Terrible" just below it. 3 Stars was actually pretty common for glowing reviews.
Everybody keeps forgetting that lots of people write reviews, especially when you ask them to ("hey, if you liked it here, please recommend us on Google Maps"), and some of those people will be the kind who gets these Amazon questions from other customers and reply "I'm sorry, I don't know how well they fit, I bought these pants for my son but he blew up the chicken coop and hadn't had time to wear the pants yet".
a) scammers
b) people reviewing with zero/way too little context ("this is the BEST maternity ward in the universe!!!")
Likewise, I figure most 1 star reviews have some sort of axe to grind.
So I gravitate towards the 3 star reviews - that's where the interesting stories are.
1) It looks like most of the reviewers have only reviewed a few businesses. Maybe this is to avoid suspicion, but if the accounts are fake they seem underutilized. I didn't see any fakes with over 6.
2) On the page you linked, a several of the reviewers (Thaddues Kelly Parks, Darren Meyer, and Adilson Vierra) gave a standard glowing review but only awarded 3 stars. Also to avoid suspicion? Others gave 4.
3) All (almost all?) the fakes are within the last month. All of the extremely negative reviews are "a year ago". They are so negative I almost wonder if they might be fake too, and it might be extortion.