It actually is. People don't even live there year round. Their graduating classes are like 10 or less. I'm guessing the hackers spoof the numbers because it's not easily reached and there are probably a lot of unused numbers.
Same deal here. I keep adding the Block Island numbers to my auto-reject list and then they just populate a new spam number. I've called back and selected 9 to be added to the DNC list. To no avail. It's even extra frustrating because I've put my cell phone on the National Do Not Call Registry MULTIPLE times and I still get these Robo-Calls, Recordings, etc.
Never answer the phone or call them back. Once you do, they know it is a person and will keep calling. Forget about the DNC registry. Will not work because these [***] are spoofing numbers.