I just thought some of it was interesting -- especially in a world like today where privacy is a valuable commodity that must be fought for tooth-and-nail.
Actually, it might be permissible to use "mental reservation" in cases where the company doesn't have a right to the information. As far as I know, that's the only time you can use "mental reservation".
Holding back the truth to someone who deserves to have the information is simply lying -- a form of injustice.
Matthew