Apart from personal experience working in grocery stores, where nobody really cares, there is this: http://marga.voxpublica.org/2012/08/shoplifting-and-magnetic

Apart from personal experience working in grocery stores, where nobody really cares, there is this: http://marga.voxpublica.org/2012/08/shoplifting-and-magnetic-anti-theft-devices/ http://marga.voxpublica.org/2012/08/shoplifting-and-magnetic... Depends on where you go and which mall. Strip malls are a lot less effective with countering shoplifters than the 'real' malls.