Companies want insurance to pay for their losses, and it turns out the only thing the videos find on self-checkout stands is that customers are frustrated that the machine is calling them a thief, when the shoplifters, big surprise, don't stand around in line for 15 minutes to walk out the door without paying.
The loss prevention person at the door is more likely to find items you left behind than to stop a shoplifter, but insurance demands it.
And the false positives on those little loss control tags is so high that most of the time workers aren't even going to look your direction if something sets it off. Once again, this is all crap required by insurance.
Shoplifters don't care about any of this. They just grab what they want and leave.