documentation or rules or instructions are not easy to write. sometimes the writer is too close to the subject, and assumes what is obvious to him does not need to be written down.
for example, I have been looking through the rules concerning the modern american longbow class. I can't find anything describing the permissible materiel for the bow. Should I assume that anything goes, maybe even foam filled carbon fiber? the arrows on the other hand, are specifically limited to wood, bamboo and feathers, while for the strings, "There are no restrictions on the bow string construction or type of materials used.", so even with no limitations, questions about materiel's have been addressed.