For instance I have in hand a can of "Jumbo Straw Mushrooms" from Taiwan. Unlike most canned goods it has two weights

• Net Weight - 15 oz
• Drained Weight - 7.4 oz

.The barrel of olives says "Net DR Weight 5 Pounds" and with liquid it weighs at least 7 pounds (I don't have a full one right now to weigh).

From these and other examples I conclude liquid is included in "Net Weight" unless the label specifically says "Drained Weight" or "DR Weight".