It is a good practice to start what we call “Hasslehoffing”

It is where you change the background to a picture of David Hasslehoff every time someone leaves their PC unlocked for a long enough time to change the background. The more it happens, the sexier he gets.

I urge other colleagues to do the same. The only defense there is against that is to lock your PC every time you leave your desk. It really works.

Did it also label real phishing mails?

Because those tests are send out for a reason. And in my experience, developers are some of the worst at cybersecurity.