I disagree. Every policy I've ever purchased, I've been sure that it covers racing. Nothing would be worse to have something like that end a claim if it came up. At least the last time I got a policy (two years ago) finding an insurance policy that covers a sailboat while racing was quite easy and not expensive. My Progressive policy for my A-cat and my Hunter monoslug covers racing and it's about $250 / year.
I just switched my N-20
from Us Sailing's deal to progressive(who already insured my A cat) and it was about half what B,G&B (US sailing) wanted. I insured both for about $60 more than what just the N-20 was. This was also with full racing disclosure for coverage.