Starfleet has many strengths. As an organisation it has done an overall good for the galaxy: that is statistically indisputable. However, when it comes to discrestion I fear that Starfleet remains lacking.
I understand nuance, of course, as Vulcan as the Prime Directive may be, I myself can imagine several situations in which strict adherence may create an insurmountable moral quandary. That said, I cannot imagine any situation which might require providing a list of the major cities on Vulcan to any member of a pre-warp society.