Shrink is real for sure. Part of my store managers bonus was based on their shrink.
When I was VP at WM, our security team gave classes on how to handle a shoplifter.
With that written, most shrink though was internal. I remember canning a store manager for stealing a Zodiac boat. It took awhile but the security dept got to the bottom of it.
The manager had been with the company for about 20-years. I can't him and guess what? His brother was the Director for the Jets football team. At the time our CEO was the former directors of the 40ers football team. I received a phone call from the CEO strongly encouraging me to rehire the manager. I didn't.
Three months later I was canned due to a "reorganization" of the senior management team. No big deal, I made out like a bandit.
However, getting back to the thread, shrink is a big deal in the retail world.