The main problem these days is you have no idea if they are carrying knives, I would certainly NOT get involved, purely because of the uncertainty of weapons they could carry. My local Boots have no security on the door, and are targeted on a regular basis, think the staff got fed up of chasing them (and not being able to catch them). My nephew a few years back was outside this same Boots and caught a youngish man, after the staff had shouted, as he left the store, my nephew jumped on this man, sat on him until the police arrived and earned himself a photo in the local paper ( not sure I would have done that, because of recriminations) needless to say he moved away not long after the episode with the shoplifter. But I have heard that Boots will not pay for a security guard, so what do they expect?