At a drive thru, make your order as per usual (try for something small to avoid suspicion). When you get to the window to pick it up, the goal is to make a huge misunderstanding. Tactics include using a heavy accent, acting foreign, or simply acting confused and telling them that what they’re handing you is not what you ordered. Confuse the workers by poorly explaining that you ordered something different, but ultimately act sincere and offer to pay for their mistake and take the wrong item anyway. Chances are the employees will offer you the item for free, or even make you a new order and give you the mistake at no charge.
In theory, this unethical life hack could work at any drive thru as long as you pay and pick up your order at the same time.