I don't know, but in hindsight I would have asked for an X-Ray. I think it was a borderline call and they went on the side of doing it because I had good insurance.
Better preventative medicine and proactive treatment is one of the perks of having good insurance, so I would expect a recommendation from a good dentist to take it into account.
Ideally there is some discussion, but at the same time, the idea that someone with great insurance would want to use it seems a reasonable assumption.