Presumably you were able to explain your case and have the reprimand expunged from your record. As long as they are reasonable in that way I don't think occasionally testing the people handling sensitive data is a bad idea.
Curiosity shouldn't preclude security, and intent shouldn't preclude policy if the operator operated knowingly.
This isn't to attack maxk42, but to engage the question head on.
Oh boy, I hope I never work in this kind of organization.