As far as the marking pocket rule, there are idiots in all facets of life, this rule was designed to help eliminate arguments when they are around playing pool.
This ^^^^^
I've never seen anyone call someone on this rule if they agreed to "call them" before the match.
It's a simple rule. Follow it, no problem.
How about putting the cue ball just over the string when breaking? That would be a foul, right? Its a simple rule, that everyone seems to be able to handle. Marking the pocket is just as simple and basic, yet it creates all this turmoil... Never fails to amaze me.