The most current version of the SMRI Rulebook is available via the link below.  It is presented in .pdf format for your convenience.

Please bear in mind that it is the competitor's responsibility to compete safely and with utmost regard to the safety of others.  No express or implied warranty of safety shall result from the publication of and compliance with these rules and regulations.  They are intended as a guide for the conduct of the sport and are in no way a guarantee against injury or death to participants, spectators, or others.

IT IS THE RESPONSIBILITY OF EACH COMPETITOR TO READ AND UNDERSTAND THE CONTENTS OF THE RULEBOOK. 

Note: Just because it's not called out in the Rule book as illegal, doesn't make it legal. SMRI Officials reserve the final call on all situations outside the written rules.