Bonded warehouses are not "government chosen companies." They are enterprises operating under the statutes and regulation for that type of business.
HOW the PD's choose which bonded warehouse to use and when to call them are issues of interest, however.
Other regulations aside, I had assumed that the police department (a part of the government) was choosing the bonded warehouse.
Does the the individual getting his guns taken away have any rights about where they'll go when the police decide to give up custody?