Is it permissible for a customer to refrain from returning dishes belonging to a restaurant if the restaurant has taken a financial "deposit" for them, and does the ruling differ based on the value of this deposit?

The dishes used by the restaurant to transport food are 'ariya (items borrowed for use and meant to be returned) and are guaranteed by the buyer. The cash deposit taken by the restaurant is considered a rahn (pledge or collateral), and it is permissible to take a pledge on an 'ariya because it is guaranteed. It is permissible to pledge money on condition that the restaurant does not use it, to avoid the suspicion of a prohibited loan combined with a sale. It is not permissible for the buyer to seize the dishes, even if they paid a deposit equal to or greater than their price, because such seizure is only permissible through a trade based on mutual consent, and due to the saying of the Prophet, peace and blessings be upon him: "The wealth of a person is not lawful except with their willing consent." So, whoever wishes to keep the dishes must agree with the restaurant to purchase them; otherwise, they must be returned.