How many real estate agenst out there have been sued because the inspector missed something?

In my opinion:

One way to avoid this is to ask your inspector if they have a "Hold Harmless" clause in their contract. Many home inspectors including myself have added this clause to protect the real estate agents. If I miss something, the agent should not be responsible. It was my mistake, not theirs. This is an easy way to let the realtor know that the inspector "owns" his/her mistakes.

Another way to avoid suits is to have a clause that states arbitration will be the first course of action before a suit can be filed. The BBB will provide arbitration to members. Most of the time the arbitration will resolve the issue.

Also, The inspector having E&O insurance may not be the best protection for anyone. Most Home inspectors limit their liability to the fee paid for the inspection.  Errors and Omissions insurance companies usually require you to file a lawsuit against the inspector.  Since most of these lawsuits are too big for small claims and too small for an attorney to take as a "commission-only" case, your client will probably be left paying for the repairs. If I miss something, and I am allowed back to the property to inspect it again, and I find that I messed up, I get my checkbook out and I pay for the mistake. 

My point is this: Insurance is not the only, or always, the best tool to protect the agent, client, or inspector.