I almost, that's almost, fell victim to this very thing. My hygienist, when I get my teeth cleaned, always tests the depth of the gum between each tooth. I think readings of 1-3 are really good, anything above 6 you don't want. So one time she told me it was time for a deep cleaning, called scaling. So I set up an appointment with a specialist who accepted my dental insurance, because it's 10% cheaper using an in network specialist.
So there I am, and he tests the depth of the gums, and he's reading off "9, 8, 8, 9", and on and on with terrible high numbers. Tells me one of the teeth needs to be removed. Then, I'll never forget this, and, lol, it just ain't true: "you have one of the worst sets of teeth I've ever seen". So, back in my car, I'm thinking, 3 weeks ago, my hygienist read off numbers like "3, 2, 5, 6", some good, some bad, some middling. How the hell did everything go south in just three weeks?!
I make an appointment with my dentist, and tell him. Man, was he pissed. Nothing wrong with the tooth the specialist wanted to pull. Everything was a scam. I did the scaling with my regular hygienist. Paid 10% more out of network, I've been with his practice for decades, and like the guy, so the 10% more I pay is OK. If I'd known my hygienist was as good at scaling as any specialist, I would have gone that route to start.
That was a close call. If I had not had the gum depth just measured a few weeks earlier, I might have been had.