Final answer:
The action that you do not need to witness a customer do to prove shoplifting is paying for the items.
Step-by-step explanation:
The action that you do not need to witness a customer do to prove shoplifting is paying for the items. In order to prove shoplifting, you would need to witness the customer conceal merchandise, remove security tags, or leave the store without paying. These actions are indicative of shoplifting because they involve attempting to take the merchandise without paying for it or attempting to remove security measures.