Many dentists ago for me but they got a new contraption that could measure enamel thickness. They waved this wand around in my mouth and told me that I was in need of (4) fillings. Now I have always had thin enamel so it's not unusual to need some fillings but I didn't trust this process at all so I told them I'd mull it over and call back. Waited 6 months for next cleaning and mysteriously I didn't need any fillings at all despite having no work done.

I don't think it is necessarily done intentionally, but it's good to be a tiny bit skeptical especially when new factors are involved.