It is not unusual for an Employer to ban certain items from the premises. Cameras, guns, recorders, etc. You want to work for an employer, you follow their rules. The camera is not required for official business, and it is not unreasonable that private cameras to be banned outright from the building. It is the right of the building to inspect what comes into the building, it is private property. A shopping mall can ban cameras, movie halls can ban cameras, you are free to not go there.
Now- we just had a borrible shooting incident in Tucson, and before that- in Virginia.
Do not equate a business policy on passing cameras through a scanner to come into a building with toting guns.
25 years ago at my work, one of my co-workers brought a camera into work and a second one was playing with it as they went through security. Personal Cameras are not allowed on the premises without a camera pass. Security confiscated the film, processed it, viewed the contents, and returned the finished prints and negatives to the owner of the camera after it was determined the camera was not used on the premises.