Same here. My policy says nothing about not covering contests or aerobatics.
I'd ask the broker to show me the exclusionary language.
Three things I never try to do: cut my own hair, fix my own teeth, or give myself legal advice. BUT in my opinion, if the policy does not explicitly exclude coverage for an activity, and that activity does not violate the FAR or the aircraft operating limitations, then the burden would be on the underwriter to justify a denial of coverage. You might have to sue them to resolve it, of course.
I don't agree with the premise that anything we don't explicitly describe in your application is not covered. I did not say anything about airplane camping or fly-ins on my application. Does that mean I can't go to Oshkosh?
Not beating you up or shooting the messenger, Bart. My ire is directed at the brokers. I think in cases like this they tend to give the lazy and safe response rather than digging into the issue to get an accurate answer that is legally justified.