Got a subrogation letter for an MRI I had last month for an injury at a dojo 18 years ago – how should I respond?

In 2005, I was taking aikido lessons. I was doing a forward roll at one point and was standing unsupported on my head, which resulted in herniated cervical discs. They gave me problems for a few years, but after plenty of Celebrex, it went away and only resulted in occasional stiffness.

Back in November, the stiffness turned into radiating pain down my arm. I didn’t have MRI images from 2005 – they were lost with a bunch of other paperwork over the years – and the facility’s archives don’t go that far back. I had another MRI, which my insurance approved, in December, so I could take them to a pain management doc and orthopedist for consults.

I got an info request for subrogation yesterday. The insurance wants to know if it’s the result of an injury or accident, and if yes, whether I’ll be filing a claim report. Since it was related to an injury, it then asks if I received any payment/settlement in connection, and whether I’ve retained an attorney. It also asks for the details of the accident: date and time, city and state, what happened, and whether it was the result of a hazardous activity.

I’m a bit worried here – is aikido in a dojo considered hazardous? Are they going to pull some kind of “oh, this is forever old, you need to provide chain-of-custody of all your health insurance since then or risk getting dropped for pre-existing conditions”, etc.?