Why do I have to set aside electronic equipment like my laptop and PDA?

Why do I have to set aside electronic equipment like my laptop and PDA?

First thing, with cell phones and PDAs, a lot of people wear them on their belt. If you don't take it off and make it available for x-ray when you go through the magnetometer or the metal detector it's going to set off the metal detector, which is going to delay somebody further at the security checkpoint. As far as laptops, there are certain things that we are looking for, and we need a laptop to go through screening because if a passenger puts a laptop, say on top of a bag, sometimes we're not able to see through that laptop just because of the density of the laptop. So they make you put it in their own container and make it available for x-ray, we're able to see what we need to see without really inconveniencing anyone.