Is it MAC you're talking about? It's been my experiences that you all are working together, so closely & it's a pretty small staff so that there isn't really much of a problem.
When I worked at a MAC store we all kept our stuff in the back (permanent employees had lockers). I never had a problem there...except once, one of my friends & I mixed up coats. There was no camera in the back cause it was also the bathroom.
At Macy*s we all have to carry clear bags...everyone puts their stuff in a drawer behind the register. As far as I know, we've never had a problem w/ theft, but I would still keep what you bring down to a minimum...I leave my purse in my car's trunk & just bring in my cell phone, iPod, money, a credit card or two & a lipstick/gloss/mirror for quick touch ups, and most of that I keep in my belt/pocket.