For the purposes of this section, the fact that a vessel has become subject to pursuit as provided in section
1581 of this title, or is a hovering vessel, or that a vessel fails, at any place within the customs waters of the United States or within a customs-enforcement area, to display lights as required by law, shall be prima facie evidence that such vessel is being, or has been, or is attempted to be employed to defraud the revenue of the United States.