Does a non-profit all-volunteer organization need insurance?

I am treasurer of a non-profit whose sole role is to raise funds to support the local symphony orchestra. The non-profit has no employees, owns no real property and has assets currently of less than $130,000 (much of which is donated annually to the symphony). An agent insists we need a $500,000 policy to protect board members against lawsuits alleging a breach of fiduciary duty or misapplication of funds. The two-year premium is $2,300. This seems excessive and even unnecessary to me. What is the view of the community experts?