There’s a story told about Butch Cassidy compatriot Matt Warner…
Matt was tending bar in a Price, Utah speakeasy during the height of Prohibition when two men in suits walked in and ordered drinks. Warner poured a couple of shots—which the men then poured into vials. They announced that they were federal alcohol agents, gathering evidence against the establishment and Warner.
Warner pulled a pistol and placed it on the bar, giving the men a couple of choices. Pour the liquor back into the bottle, or drink it. Or else.
According to the tale, they emptied the vials into the bottle and hurried away.