Stylistic question

["Guy L. Steele, Jr." <GLS at MIT-AI>]

    Date: 9 JUN 1979 1138-EDT
    From: Moon at MIT-AI (David A. Moon)

    Currently it is legal to take CAR and CDR of closures and entities,
    and you get various interesting things.  Should it be changed to be
    an error, and functions provided to get the interesting things?
Yes.  Moreover, it seems to me that taking the car or cdr of
an entity should result in sending the entity a CAR or CDR message,
n'est-ce pas?