I'm not sure that it says that a user cannot modify the object, Laszlo. See:
where it says you can not distribute modified material ... but does not say you cannot modify for your own use.
Thus, people can still provide instructions here about what lines of code to insert, as I read this... as long as the reader does the insertion/editing themselves and does not distribute the result.
The biggest problem that I see is when people who modify an object for themselves only, have every intention of honoring the license, but then send a PLA to a colleague... even in the same office. Since the PLA contains the modified object, the license is then violated.
The fact that a single firm cannot internally modify an object for their own internal use... whereas a single individual can do so ... seems too strict.
All seems very awkward.