First impressions on a NOAA tour

Boulder Scientific Tour - Vox

But back to the NOAA. We first stopped at the security station outside. A security officer came onto the bus and said that we were all going to have to get off and go through a metal detector, so anything we didn't want to take through the metal detector we should leave on the bus. Being the good Americans we are, we didn't question this, but did as we were told. We were all given temporary name badges, and went through the metal detector, then got back on the bus which took us on to the main building.

Now... since we could leave whatever we wanted on the bus and were given an opportunity to retrieve it before going into the main building, can someone please explain to me what the hell the purpose of the metal detector was? These people need training on how to design a security checkpoint system, because this ain't it.