Folks should consider insurance provisions carefully. Most insurance policies have fairly lengthy exclusions. Mine says coverage is excluded or does not apply "if you know the aircraft is not certificated by the FAA under a Standard Airworthiness Certificate in full force and effect while in flight".
I am not an attorney but exceeding the W&B/GW of an a/c could be interpreted as being out of conformance with the Airworthiness Certificate. I have heard gross weight exceedence arguments from insurance carriers before. Talk to your provider. I bet you won't be covered. The points made by others with respect to normal and utility category g load maximums also are important, especially with older aircraft.
