Joey,
1st item in red... As mentioned before, a rule stating to have morality will not have an affect on a moral person (since they don't need to be told), nor will it have an affect on a non moral person.
2nd item in red...Only players without moral would say "I didn't call the foul on myself because it's not in the rules". I doubt any thief would say "I only robbed the place because the door was unlocked, so I didn't think it was illegal".
Integrity is doing the right thing, even when no one is looking.
Because we are only human, our level of morality may differ from person to person and our will to toe the line may differ as well.
The LOCK on the door won't deter the career criminal but it will help to deter a basically honest and decent but desperate man or even a needy man from making and doing an impulsive and dishonest thing. (As will the self-reporting rule on fouls).
I know good and decent pool players who have in the heat of battle, on occasion, chosen to remain silent about a foul that they know they committed. Their reasons are there reasons but their excuse is that "They are not required to call a foul on themselves."
Let us help to elevate our sport, rather than to provide loopholes where a player chooses to remain silent over a foul that they know they committed but chose not to report.