If there was a legal liability for writing up defects, most schools would close tomorrow
Many times I was told in no uncertain terms to NOT write something in the logs.
I suppose the owner could be held liable if he rented the plane to somebody and the renter got killed as a result of the non-notification, but I really have no idea how much evidence would be needed to make it stick. If something is not written up, nobody can say that such and such person knew about it.