Thanks, Peter, I enjoyed reading this fascinating account of brutal sports over the ages. It helps me understand the degree of brutality that still exists in a number of modern sports, some of which are very careless of the health & well being of the players. Thank goodness that that is still changing for the better.
As an historian of science who did some work on Maya astonomy in the sixties, I agree with several other commentators here who have suggested that it is unlikely that the Maya rules of play are known quite as precisely as you have set them out in this account. For example, although human sacrifice did occur with the Maya, In particular, I very much doubt that it was as common or as systematic as you seem to depict it.