I doubt they knew there was a swimming ban. There were no signs anywhere that said "No Swimming." I was on Cabarete beach all through both hurricanes and made videos of them and posted them on Youtube. There are no signs, and no one to stop you from going into the water. The police only come out and wait for you.
I bet plenty people jumped into the water on Wednesday & Friday without having any clue whatsoever as to not being allowed to swim. Until they got out and were arrested, how would they know? There are no lifeguards blowing their whistles at you telling you not to go in. There are no people stopping you from going in.
It's a Catch-22. They arrest you once you come out of the water and only then do they inform you that you broke the law.
My guess--and it could be way off, but i see crazier sh1t every week--is that the police simply waited for them to come out of the water and arrested them without warning them not to go back into the water. Most tourists do not speak Spanish. The police do not speak English. The police love these golden opportunities to make a little money off the tourists--who have no idea that they are breaking the law--which, by the way, is just put in place the day before the hurricane!!
Over night, the police have a golden ticket to make tourists pay what amounts to "Glorified bail money" to stay out of jail until their court date--which could be after their flight is supposed to go back home--back to work. Now they got you by the balls!! It's scam. It's the mother of all scams, and it goes on every single weekend here on the north coast--but particularly in Sosua and Cabarete.
The scam works like this...
The police find people doing something that they had no idea was illegal--i.e skinny dipping, having sex on the beach, Surfing or Kiting in a hurricane or tropical storm, etc. The police immediately arrest them when they come out of the water. Naturally, the police always give the person, or persons, the opportunity to buy themselves out of jail--which most people will do. It's the perfect opportunity to supplement the police income in a semi-legal way. They tell you things like, "What you just did is "Illegal." You are not allowed to skinny dip, take your clothes off, go swimming, etc"--just insert something here__________.
Now, they got you just where they want you. And what they want is money. Plain and simple. They don't give a crap that you're swimming, or Kitting, or Surfing, or Skinny Dipping. All they care about is that a rule/law was put up the day before the hurricane or tropical storm saying "No one is allowed in the water." They then use that rule/law to arrest anyone and get money out of any tourist they can. It's the perfect opportunity to supplement their income. And they do it over and over.
I saw it happen to 6-guys at my bar seven years ago over something so ridiculous, so arbitrary, such a Catch-22, that you have to laugh at the absurdity.
Frank