There are cases when one does not want to output reader labels for shared structure, such as when you don't care (and want the output to be more legible), or when you know that the time or space requirements to construct the table will be too large.
We could offer a parameter to control this, or have separate procedures (as in CL).
We now have write (which represents cycles but not shared structure), write-simple (no datum labels), and write-shared (full datum labels).
We voted for write-simple.