; and (2) arranged not to interfere with the needs of Congress. (b) Expenses and liabilities The sponsors of the Memorial Service and Exhibition shall assume full responsibility for all expenses and liabilities incident to all activities associated with the events. 4. Event preparations Subject to the approval of the Architect of the Capitol, the sponsors referred to in section 3(b) are authorized to erect upon the Capitol Grounds such stage, sound amplification devices, and other related structures and equipment, as may be required for the Memorial Service and Exhibition. 5. Enforcement of restrictions The Capitol Police Board shall provide for enforcement of the restrictions contained in section 5104(c) of title 40, United States Code, concerning sales, advertisements, displays, and solicitations on the Capitol Grounds, as well as other restrictions applicable to the Capitol Grounds, in connection with the events.