Nice review – thanks for sharing!  I learned the Norwegian “shoe rule” the hard way too.  I don’t remember what ship we were on, but we weren’t allowed in an included dining room because I had nice sandals on.  Our room was one deck away and I had loafers by the door; I was back in two minutes but they refused to seat my wife until they saw I’d complied.  They explained that this rule only applied at one included and one specialty restaurant (the French one) and sandals were fine at every other dining venue.  We’ve found you can often get seated right away in the “shoe restaurant” while there’s a wait elsewhere.  So now I wear some comfortable loafers just in case – but they still can’t make me wear socks!