What is the ruling on spraying vinegar on red dates while they are still on the palm tree to accelerate their transformation into rutab (soft, moist dates) and reduce labor costs?

It is not permissible to spray vinegar on unripe dates (balah) to hasten their ripening into ripe dates (rutab) for two reasons:

Firstly: Deception (ghish); because the unripe dates lose much of their taste and benefit, and the buyer is unaware of this. The Messenger of Allah, peace and blessings be upon him, said: "Whoever deceives is not from me."

Secondly: Harm; because vinegar absorbs fats and fluids from the body, and the dates lose their nutritional value. It may also cause damage to the liver and digestive system.