The moderator agreement, located at https://meta.stackexchange.com/legal/moderator-agreement, has the following text at the bottom:
I acknowledge and agree that I am an independent volunteer moderator to [site] and I am not an employee, agent or representative of Stack Exchange Inc., and I have no authority to bind Stack Exchange Inc. in any manner. Stack Exchange Inc. reserves the right to terminate my privileges as a moderator at any time without warning.
Since this paragraph obviously doesn't apply to SE employees who gain diamonds by virtue of their employment, and since the agreement is a legal contract, such employees are thus not bound to that particular agreement.
Given the specific privacy expectations outlined in the agreement, it makes common sense that all moderators should abide by it, no matter how they get their privileges, whether it be via a community process or by gaining employment at SE.
Are employees subject to a similar agreement? Is it part of their employment contract? Or is there another agreement to sign, since we have a lot of staff members who aren't moderators? If there is another agreement, how equivalent is it to the community moderator agreement linked above? If they aren't subject to any such agreement, are they generally expected to abide by it for ethical reasons?
Finally, if there is an agreement, what sanctions can be taken against staff members who violate it? Is it immediate cause for being fired? If not, if their position doesn't require moderator privileges, will they still continue to be non-moderator staff members?