That sucks. I'm not sure what sucks more though, that the crime rate is high enough that they feel the need to do it or that they just assume everyone is a criminal. I've had this situation happen when I was in college, especially with the book store. At the time, I found that just telling them "no" worked about 90 % of the time. Of course, I was also being confronted by another student, not a uniformed security person. I can't speak for the law where you live, but here, there's nothing legally (that I'm aware of, anyway) that allows a store to hold your personal effects while you shop. For future reference, maybe look in to what the laws are in your area and point them out next time if they work in your favor.