It's a legal term.

https://en.wikipedia.org/wiki/Meeting_of_the_minds

"[...]it refers to the situation where there is a common understanding in the formation of the contract."

I realize you're not the one who used the phrase, but I don't see why a customer of a doctor or plumber would need to be a doctor or plumber themselves in order to have a meeting of the minds in this sense. Nor do I see how having the government certify the doctor or plumber helps with this issue.