Alot of people got away with that when i worked at a walmart. Walmart has a strict policy not to stop shoplifters unless you're a high up member of management, but even they are limited as to what they can do. I known of a few that got fired for running after and stopping people.
I can vouch that this is the same in most retail stores. I work at Kmart (I'm not exactly happy about it, but a job's a job until February and basic training), and we can't even say anything if we see someone taking something they didn't pay for. Unless security is actively watching them, there isn't a single thing we can do.
Oh sure, we can go up to someone security points out and ask if they need help, but we can't say "Hey, put that back."
I saw a kid (probably 7 or 8) take a video game out of the cheap bin up front and put it in his coat. I said "Can you take the game out of your coat and put it back please?" That's the only time I broke that rule, because kids need to know we're watching them do stupid stuff.
tl;dr retail wage-slaves have no power to stop, chase, basically even look at shoplifters.