For security reasons. Recycling services are not designed to provide security. Generally, recycling services use open collection containers, which are unsecured. Generally, the employees of recycling service companies are not security-screened personnel. Paper is taken to the warehouses, which are accessible to other people, and the paper is then sorted for grade. The courts have ruled that once you place your material into the trashcan, recycling receptacle, or dumpster, you lose all privacy rights to that information, no matter how sensitive or proprietary it is. The laws on public domain protect the people taking the information – NOT YOU! You may be held liable for negligence if the discarded material does harm to someone.