What is the ruling on giving a pre-paid meal ticket to an unregistered friend to eat, and what is the ruling on taking leftover bread pieces after others have finished, and what is the ruling on accepting an extra piece of meat from a restaurant worker for an unregistered friend eating with me?

It is permissible to give your meal ticket to your colleague for free or for its price, because you own it and your colleague is entitled to the service.

It is also permissible to share your meal with your colleague and to take the leftover bread on the tables that its owners left willingly, as it then becomes the property of whoever takes it, and it would likely be thrown away otherwise.

However, if the worker gives you more food in your meal than you are entitled to, the default is to forbid it. But if this happens occasionally, we hope there is no harm in it, especially if the officials permit it, or allow a student to bring a guest.