In Hawaii we have two taxes that apply to short term rentals. One is called the GET (General Excise Tax) and is pretty much the same thing as a sales tax. It applies to almost everything bought and sold in Hawaii. It is about 4.25% but actually varies a bit by county as of the last year or so because the counties can now add a surcharge. The second is called the TAT (Transient Accommodation Tax). It is about 11% or more, I have not kept track. It applies to all rentals of less than 180 days. Each tax requires a license from the state and quarterly or monthly filings/payments.
Hawaii has really started to crack down on vacation rentals. About 5 or 6 years ago they started requiring all vacation rental ads to include the tax license number. For example, if you go to:
Comfortable two bedroom condo located in the Princeville Resort at Pali Ke Ku - Princeville
You will see the ad includes the line:
Registration Number: TA-008-552-5504-01, GE-008-552-5504-01
Those are the tax license numbers. I can then go to
https://hitax.hawaii.gov
Enter T-008-552-5504 as the new customer ID (not a typo, T not TA or GE) and I will find that the owner has the proper licences and is in good standing.
That's just an example. When I previously did that for the place they were staying I could not match the numbers to an actual license. It's possible he is paying his taxes and there was just a type or something.
It is very common for people to try to avoid paying those taxes and the state is getting very aggressive.