Not smoking indoors is without question, we are used to that here, but alcohol kept in small leakproof containers like hip flasks don't have to be swigged, the contents just need to be tipped in a cup as many people carry those anyway for day to day consumption and I certainly do when I am out fishing or camping in the middle of nowhere, it does brighten the mood when it is cold and wet. But I hardly think everyone is going to be watching everyone else in case they snook in illicit contraband, most likely they would be tending to their own affairs, but what do I know beyond common sense, I have not experienced such conditions that would merit such a move as bugging out to a safe location en masse as living on one's own one tend to look after oneself and food....
Quite right most evacuees would be busier tending to their own affairs. That said the shelter management would be very vigilant. As to seeing to your own food and water, the shelters provide little (if any) food. You're expected to bring your own. Blankets as well. They are exactly what the name implies, "shelters." A solid building in which to take shelter from the storm's fury. They "might" have limited supplies of food and blankets but it would indeed be very, very limited.
Just checking the weather channel now and the advisories for those in the Keys (and a bit farther north in Dade County) are as follows: If sheltering in place, stock at least 3 days food and water; if evacuating, take at least 2 WEEKS food and water! And Isaak's barely expected to be a Cat 1 when it hits the Keys.