Is it permissible to relieve oneself in restaurant restrooms and use their facilities without purchasing anything, knowing that restaurants provide them and do not explicitly forbid their use?

The origin of restrooms in restaurants is that they are designated for customers, but it is tolerated for non-customers to enter them with the permission of the restaurant owners. The person entering must explicitly ask permission from the person in charge and not pretend to be entering to eat. If permission is granted, he is allowed to use the soap and tissues accordingly, though it is preferable to refrain from using them. If it is known that the restaurant owner does not wish for this and only grants permission out of shyness, then it is not permissible to enter except in dire necessity, based on the Prophet's (peace be upon him) saying: "The property of a Muslim is not lawful except with his willing consent." As for a state of dire necessity (fear of perishing), it is permissible to enter and use what is necessary. Indeed, jurists have stipulated the permissibility of taking another's food and water, guaranteeing its price, if a person is compelled to do so. If the owner does not offer it to the person in dire need, the person in dire need is permitted to take it, even by fighting. The person in dire need is a martyr if killed, and the fighting of the owner is in vain.