“… a significant number of corporate IT personnel snoop sensitive data, and nearly 9 out of 10 would take company secrets and remote access credentials with them if they were fired.” (link) More data to scare CEO’s and senior managers. The IT department has an incredible control and access to all kinds of information. Why is this a surprise? Your IT staff should not be hired like the rest of your staff. Much more care needs to be taken. Different levels of access should be given and of course special non disclosure agreements need to be signed along with non competition agreements.
So who polices the police? This puts even greater onus on choosing senior IT staff. Pick them carefully and fire them even more carefully. Or have measures in place to lockdown their computers before you fire them.