Reading the fine print on our trailer insurance policy it mentions that the trailer has to be inspected and checked every 30 days. For those who store their trailer in an RV storage lot you may want to check your policy. I make a point of checking my trailers monthly and taking pictures as proof for the insurance company.
We work through an insurance broker but the policy is through Elite Insurance, Do notice I am in Canada but I would not expect our policy to be unique, insurance companies look for any reason to refuse a claim in my opinion.