Truly, the only way to know for sure is for the business owner to carefully read their insurance policy, and to verify coverage (or lack thereof) with their insurance agent. As Baygo said, you have to find out not only what is covered, but what is not.
When I worked as an underwriter, I learned that an insurance policy was written to define coverage, define what's not covered (called exceptions), define what in an exception may actually be covered (an exception to an exception), etc.. Most importantly, always remember that insurance policies are not written by insurance company personnel, but rather by lawyers.
Dave