Notwithstanding any other provision in this part, a DOE employee may not authorize or approve, require another person to authorize or approve, or advocate the authorization or approval of, payment from DOE funds of travel expenses of a person who is not a Government employee and who is (a) the DOE employee's relative (except in the case of payment under § 1060.101(a)(4)), or (b) in the case of payment under § 1060.101(a)(1), a DOE contractor or a DOE assistance award recipient or the employee of a DOE contractor or a DOE assistance award recipient unless the travel expenses are incurred with respect to matters outside the scope of the contract or assistance award, as the case may be. (See also § 1060.101(e).)