Water

Neither Gowrie Barden (USSA insurance) or the David Agency (formerly Meyers Briggs) require individual liability insurance as a pre condition for the OA to purchase regatta liability insurance.

Property owners, may require individual insurance to use their property. Many YC's or marina's will require liability coverage as a condition for keeping your property on their property.

Property owners often require the OA to insure their property for booze, and other liability for the event. That insurance is separate (On the Beach Insurance) and costs you another 400 plus 50 (or so) to name the property owner.

I have never seen a requirement for an individual to have liability coverage.

International events are different. Many examples of one competitor with or without insurance telling the other to get lost (see Mike Hill's story). Events like OCR require you to hand in a zerox of your liability coverage. The USSA OD individual insurance program was modeled on the coverage that the Tornado Olympic guys needed for international events. (it includes boat charters, chartering,)

If you want to do the insurance proof... I think you have to go all the way and collect a copy of the proof of insurance.

Note added.
Dave, that is not the story I got from Chubb.. or David. This was three years ago. Again. If were true... almost every YC would require racers to show proof of insurance... Fact of the matter... all of the CBYRA YC's on the bay DO NOT MENTION LIABILITY INSURANCE nor does the Key West RW NOR.