Any promotional benefits or materials received from a travel service provider in connection with official travel may be retained for personal use, if such items are obtained under the same conditions as those offered to the general public and at no additional cost to the Government.
41 C.F.R. §301-53.2
Note to § 301-53.2: Promotional benefits or materials you receive from a travel service provider in connection with your planning and/or scheduling an official conference or other group travel (as opposed to performing official travel yourself) are considered property of the Government, and you may only accept the benefits or materials on behalf of the Federal Government (see§ 301-74.1(d) of this chapter).