Amazon and prisons

From Amazon.com Help: Shipping / Shipping Restrictions:

Prisons

Amazon.com delivers to penitentiaries, but we strongly suggest you
contact the prison first to confirm that they accept deliveries and to note any
special regulations the prison might have. Some prisons don't allow delivery of
hardcover books. Others place a limit on the number of items contained in a
package.

We're unable to affix any special labels or instructions to the
packages and on the outside will indicate only the destination address, our
company name, and our return address. We also cannot allow gifts to be sent
anonymously to inmates; the sender's billing address will appear on the order
invoice.

Because inmates cannot sign for deliveries, packages must be sent
via U.S. Mail. While Amazon.com often sends packages via U.S. Mail, we also use
UPS, FedEx, and Airborne/DHL. Unfortunately, there is no way for customers to
request a specific shipper. To avoid delivery problems, you might consider
having the items shipped to you and then shipping them to the penitentiary via
U.S. Mail.

It makes me wonder how many people actually order items for inmates and send them directly to the prison, and who these people are.