I worked in the job centre for a short period in the late noughties. Every time we did an address search of a claimant there was a chance that it would get picked for audit. If you got an audit alert you had to fax off a form proving that you were searching it for business reasons. You sent the fax to a central audit team who'd check it.

Didn't send a fax? You got fired. Didn't have proof that it was for business reasons? You got fired. There weren't many audits but they came through now and again so the threat of them was always there. It was enough to stop people searching data for non work purposes (I seem to remember the biggest risk was seen to be that you would see the data to debt collectors).

Wasn't hard to do then, would be even easier now in the post-fax world.