Here is the standard info we get when our reservations are confirmed.
"NO FLIP FLOPS AT ANY TIME
LUNCH: Fashionable casual attire, however, NO tank tops, cutoffs, swimsuits, bare midriffs, sweatpants or beachwear. Walking length shorts and jeans are OK provided the cover undergarments and are not faded or torn.
DINNER: Gentlemen: Collared shirts and trousers are required.
Women: Informal dresses, or pants with blouse.
Shorts or short pants are not acceptable at dinner for men or women
"
Also, we have seen a woman in a top with spaghetti straps asked to change, I believe it falls under "tank tops". Short pants = Capris. (I have specifically asked.)
And "flip flops" are defined as not having a heel strap.