::::::You would guess wrong... PHGL New York is one of the three jurisdictions I have visited (the others being my own GLoNY and GLCT.) and they definitely do NOT have such a clause.   As to Prince Hall Mo., am I correct that you are thinking about DeHoyos's statement?  I do understand what DeHoyos says... but I suspect that what he means is that their ritual originated using Duncans... I say this because I am familiar with the history and developement of masonic ritual in gerneral, and I have yet to find any Grand Lodge that did not change and "update" their rituals from time to time.  I see no reason why PHMo. would be any different.  I am not saying their obligations do or do not contain your clause, but I would not use DeHoyos as "proof" that they do. 
 ::::::But that is really besides the point. Even if they do have a "keep the secrets except for murder and treason" clause, you are only talking about one jurisdiction among many.... and one GL's obligation is not typical.  That is the point of doing this by synopsis instead of by example. What we are trying to do through the synopsis is give the reader an idea of what is commonly included in most Obligations, not what is included in those of only one or even two jurisdictions.