The VI's are great, bring common sense & use caution.
Keep in mind that while the US and BVI's are certainly beautiful places and visited by thousands annually, the same precautions and protections found at mainland resorts and business in general should not be assumed to exist here. Use common sense and be wary of risks.
At beaches, if you see locals approaching beaches in small boats offering to take you water skiing, this is great, just make sure you and your kids aren't "run over" while swimming and snorkeling. I've seen this happen. The hotels don't attempt to control outside vendors and don't have real control of their beaches. So watch out.
In you accommodations, open the door and have your family wait outside while you enter cautiously and open some windows, make sure the place isn't full of toxic fumes from pesticides. Those applying pesticides have no training and not the least bit of knowledge about what they are doing. Case in Point, Spring 2015 when the Edmonds family of Delaware entered their lodging and were poisoned by Methyl Bromide. They all went to the hospital and two had to be life-flighted back to Delaware. This story can be found on line.
Of course, leave your valuable jewelry and watches at home. Don't trust in-room safes. All these comments go for all the Caribbean from East to West, North to South.
I've never seen any "locals" approach beaches offering water skiing in USVI. EVER.
Beaches and Resorts that are tourist attractions have their own licensed businesses/concessions that offer and operate water sports activities and must be USCG approved if taking anyone out on a boat for any activity.
The case in point that the OP states about the pesticide poisoning was the one and only, unfortunately tragic event, that has ever happened in STJ in USVI. That triggered lawsuits and a tightening of laws, rules regulations governing pesticide use in USVI.
Yes, it good to be aware of your surroundings and take precautions, anywhere you vacation.
Haven't heard any issues with in room safes.
Lots of beaches, I usually hung around Lindbergh but would go as far east as Sapphire and sometimes around to the North side. I had a 13' Boston Whaler with a 55hp Evinrude/Johnson hybrid engine. I kept it at Shoreline.
DLCA and USCG? Why would I bother to register? I only had interactions with the Coast Guard twice in my 10 years of boating, once they were on shore waving us down for driving inside the markers for the beach, and the second time was this from my book:
Richard, Chris and I were in Magens Bay near Tropaco Point, on a stormy day, having fun water-skiing and girl watching, when my engine quits. We try desperately to get it started, but have no luck. We get closer and closer to the rock face of the at least 100' high cliffs, wondering what to do.
When we get about 100' from the rocks, I tie one 75' and two 50' ski tow lines to my anchor that has a 50' line and 15' chain. I throw the anchor overboard, hoping that it will catch something. At about fifty feet from the rocks the anchor catches on something; the line is pointed almost strait down and its hold is obviously tenuous.
After waiting there for about four hours, about a hundred people are looking down at us from the top of the cliffs, not doing anything but gawking. Finally, Dale comes around in his boat and tows us to Magens Beach.
When we get to the beach my father is there along with a Coast Guard officer. The Coast Guard officer tells us, "You have to come with me and fill out a report." I am pissed and ask the officer, "Where's the Coast Guard boat? Why didn't you come out and rescue us?" He tells us, "It's too stormy to bring the boat around; you need to fill out this report."
I blow up and tell him, "F*** you! I'm not filling out any f***ing report!" My father says, "You shouldn't talk to him that way, he has a gun!" and I say, while looking the officer strait in the face, "F*** him, I'll take his f***ing gun and shove it up his f***ing ass!"
We walked away and the officer did not say anything else to us...
That is the extent of my experience being on the water for 10 years with the Coast Guard of the USVI.