If they only took a hidden purse then they watched you hide it. Same thing happened to my wife a few years ago. They basically only do this in order to A)Get whatever cash you have and B) Use your credit card locally to buy gas or some item, usually in the first 15 minutes.
So if you want to prevent this from happening again then pay attention to the people watching when you or your wife go to "hide" the purse or something. Also those of you that have phones, Ipods, tablets or nice GPS units in plain sight you are now just a target.
Note: After talking to police and learning about this type of crime and the methodology of it we started searching the side of the roads up to a mile away from the crime. You see, my wife had two brand new pairs of prescription glasses ($1200 worth of trifocals) she had just picked up + pictures she was taking to get scanned of her grandmother. We found the purse in one of the ditches beside the road about a mile from the scene of the break in. Inside everything was still there minus her VISA credit card and about $100 in cash. Even her wallet was still in there with all her other cards.
Right after it happened, we started calling everyone and then called LifeLock. We were assured we would be fine (by LifeLock) and the only charge so far was for $75 at a gas station. The VISA people took care of that and we still have a LifeLock subscription.
Moral of the story: Watch before you hide stuff.