JB highlights the reason that, at one time, I had a BCA rulebook + 1pkt rules printed out and kept in my pool case. This was just as protection against BS during gambling matches, even involving low stakes.
Also, lack of commonly adopted rules, even amongst organizations playing the same game, add to confusion (for example, in Lexington, there is the ACS & BCA 8 ball leagues - one is rack your own, one is not, one is ball in hand after the break after a scratch, one is not - I can't ever remember the difference ha ha ha).
Lastly, and perhaps tangentially, a lack of common rules and common understanding (especially amongst casual players and bystanders) is the single strongest reason that new pool games (yes, BB) are almost always going to be D.O.A. If most of the public don't even know the rules of 8 ball, the most popular game in the US by far, then how can it possibly be good for pool to explore other games? Just my opinion of course.
Anyway, cheers to you JB...labor day approaches and I don't know about you, but I need a break...