No weapons at the medical facility, please.

Since our daughter was born, our insurance has changed a little. As a result, all the prenatal blood testing is done at some place that specializes in blood tests. Inside the door is a sign:


Has this been a problem there before? Why have a sign pohibiting weapons, if nobody is bringing weapons in the first place? This is probably a template used by every office of some corporation across the country. Still, I wouldn't have considered the possibility of knives and guns in the waiting room if not for the sign clearly stating that they're not to be there.