Yes indeed Bea I think that is the issue.
I understand Dev would like to make a pedigreegiver with modify on the object unticked.
Therefore the current pedigreescript can not work in an object which is not modifiable as the end user needs to add the ID of the cat or box in the description field of the object.
I'm by far not a scripter so I'm affraid making a script like that is not something I can do at least
