All of the holding cells that I have been in, have been Block walls and a steel door with an 8" x 8" window in it.
It's the actual cells(bedrooms) that are inside the cell blocks, which are the same as the holding cells on a larger scale, that have the bars on them.

I can undestand the ladies in booking wanting to place the box inside the holding cell until animal control arrived. Not everyone is into large constrictors.

Really not media worthy IMO. Just a minor mistake by the shipper, and confusing situation with FedEx and the employee at the shipping hub.