> 4. CAN X ONLY IF Y: Equivalent to "CANNOT X UNLESS Y". Similar > for (MUST, MAY, SHALL, SHOULD) X ONLY IF Y. > > [[[ This is consistent with capatilizing ONLY IF. ]]]
'ONLY IF' is defined explicitly as a special phrase, and capitalized to disambiguate whether a rule intends to use its formally defined behavior or its ordinary usage. 'UNLESS' is never so defined, and so there is no duality of possible meanings. If you mean 'unless', you should say 'unless'. If you wish to write a formal definition for 'UNLESS', you should do so before using the capitalized 'UNLESS' in the rules.
