Plain version: the disclosure duty has limits. You don't have to tell the other side what it already knows, what it should know anyway, what it says it doesn't need, or certain facts about risks the policy doesn't cover. And your opinions are never required.
Under California Insurance Code §333, neither party must communicate the following, except in answer to the other's inquiries:
Matters the other, in the exercise of ordinary care, ought to know, and of which the party has no reason to suppose it ignorant
Matters of which the other waives communication
Matters that prove or tend to prove the existence of a risk excluded by a warranty, and that are not otherwise material
Matters that relate to a risk excepted from the insurance, and that are not otherwise material
Two examples: the insurer's own inspector reports painted-over sprinkler heads to the insurer, so the owner's silence about them is not concealment, because the insurer already knows. An applicant for a policy that excludes earthquake need not volunteer a seismic report that has no bearing on any covered peril, because it relates to an excepted risk and is not otherwise material.
Section 339 goes further: neither party is bound to communicate, even upon inquiry, information of its own judgment on the matters in question. When asked about facts, such as earlier losses, a party must answer; opinions are protected, facts are not.
The core duty stays in place: material facts the other party has no means of learning are not on the §333 list, so §332 still requires them to be disclosed even when no one asks.