Metal Detectors at Campus High ?

I think that the new metal detectors at our school doesn't make a difference . The school might think that with the new metal detectors that everyone will be safe . But some students can put blades in lotion and in their shoe . Cause the metal detectors does ring when you pass by with metal but the security isn't really doing such a good job on checking us for weapons. I think this is wasting time and also making students late . There is no point for them to install this into our school .