What is the ruling on listening to recordings of university lectures for the purpose of seeking knowledge without attending them, given that it is unknown whether the lecturer permits this?

The default rule is that it is permissible to listen to recorded lectures unless it is known that the lecturer does not allow it. However, if it is highly probable or circumstantial evidence indicates that he does not permit it, then it is not permissible to listen. This is due to the consideration of intellectual property rights, while acknowledging that scholars have differed regarding their recognition.