My observations (Canada, bigger city): The LP people you see (ie in "uniform") are often visible minorities, often women. They're positioned to remind you "we're watching!" not pursue any action. At best they'll call emergency services (a health event as common as theft). The covert LP people seem to be big, white, young males - the same type you see at popular gyms. They're still easy to spot because you see a young dude putting the oddest selection of products in their basket (always a basket) as the follow a "suspicious" person around. Their game seems to typically be stop the known thieves, recover stuff and kick them out of the store. Physical confrontations are limited because of liability and only rarely do they call the cops. I'd expect the experience is different in the US or other environments.