They put their children first and aren't going to risk getting arrested and imposing that situation on their children.
I have a dear friend who went through a wicked divorce and a 4 year custody battle. He finally won that battle. He smoked pot and did not drink. He gave up pot when he entered the battle and has never started using again. His children worship him and he is probably the best father to his children that I know of.
FMCDH(BITS)
Those are family values. You don't have to agree with the laws but you obey them for the sake of family.