I'd assume that G loading is part of the design process, I wish I could say what it was, but I don't have the data. But I'm sure the ship has to meet some figure like "safe for all loads below 3G's" or something similar.
I know that's how things go in the airplane world. Again, I don't have the inclination to look up the numbers now, but I'm aware of some air planes which have different categories based on their GW. Example, if you load the ship to 3000lbs, it's a Utility ship, which says it's certified for 5G's of stress. However, if you choose to use 3500lbs as a GW, you're limited to Standard category which may only be 3G loads (bank, maneuvers, etc.)
Anyways, the point I'm trying to make is if you could guarantee the ship would never see more than, say, 1.2G's, without any turbulence, under maximum maneuvering speed, then you would cause no damage beyond increased wear.
Of course, heli's don't always list "max maneuvering speed," you can't ever guarantee you won't exceed 1.2G's, or encounter any turbulence, and the ships were designed with these G loadings more as a transient than a continuous load.
Really though, as others have said, this is all moot. If you fly it over gross, and are caught doing so, the blame for future or current failures will most likely lie on you from the eyes of the victims, employers, and insurers.