The last WG I saw (Mary.Loves69) only had 1 feedback when I saw her. Loorachoop saw her when she had zero feedback. We both had an excellent punt, allbeit we were both trying to book her mate gorgeous alexya, so we were Bait & Switched.
But yes you're right , if you see a girl with zero feedback it stands to reason you're more likely to get a B&S, or to be robbed, or to get someone who's been coerced (far more likely than if you visit a reputable parlour IMO).
I'd guess that many zero feedback girls are legit, everyone has to start with a blank sheet unless they re-use profiles.. The fact so many have started at once could just be as it resulted from a group of lasses chatting about it and convincing each other to try (I know pretty much for a fact that discussions about going into sex work have became common these last few years in places like the UK universities, I've seen written reports about this, also confirmed by talking to a WG who had recently been a student.)
That said my guess would be it's slightly more likely to be a pimp behind the sudden influx, also a chance its an organised attempt to scam punters.