Oh god, I so nearly started a similar thread. I'm deeply bored of the astroturfers of all hues.
And yes, it definitely is happening.
It happened to strike me on a particular thread, so I followed a small bunch of the really obvious ones as they spammed multiple threads on the same issue, frequently with a single post, and generally with no sign of even reading never mind learning from the previous discussions.
Then I Advance Searched them, and lo, first posts within the last few weeks or days. Or in one wonderful case, they've been here longer but their other posts are mostly about how wonderful a particular private clinic is... Seriously mate, we can see you.
And I'm really not talking about people I just disagree with. I mean, JanetBrown may post all sorts of stuff I think is junk, but she's an actual MNer who's been here for years and is completely transparent in every namechange. So I may disagree with her, but I don't think she's a shill.
The astroturfers are just fucking tedious.