What is the most likely purpose for including the statement at the top of the document? to ensure that Ozamoto travels only to Colorado to ensure that Ozamoto understands that he cannot return to his home in the exclusion zone to ensure that Ozamoto knows that he cannot approach a military base

The most likely purpose is to ensure that Ozamoto understands that he cannot return to his home in the exclusion zone

An area usually will be included as exclusion zone if it's contain something that would be really dangerous if spread to other area.

Examples of an exclusion zone is the area around Chernobyl after their nuclear plantation blew up.