This is how I look at it, not saying you’re at fault, but objectively this is why I think this shit’s a big deal to them:
Whether you tell customers how much it weighs or not is irrelevant if you’ve told one person the weight, which you admitted you’ve done. Before or after the sale is also an irrelevant detail. The calibration of your scale is also irrelevant, as well as the fact that you don’t buy solely by weight. If you don’t have a certified scale or whatever the fuck(I’m sure you can’t recalibrate the certified ones), you can change the accuracy of it in 30 seconds(say you need a 5 gram weight to calibrate it, well use an 8 gram weight instead, done). Now I’ll tell you why that’s all irrelevant in your case. You buy your gold based on a bunch of qualities. If you tell one person that their gold weighs 10 grams because they asked, that person used that information in their decision to sell to you regardless of the fact that it’s not the only factor, that you even wanted to tell them, or that no one where in your store does it claim anything about the correlation of weight of gold and amount paid. The point is, if ONE person used the weight you told them in their decision to sell, the law probably states that you need a certified scale or else it would be way too easy to rip people off and you could fuck people on a case to case basis. I say probably because how the fuck would I know but logically that would be a good consumer protection law and I’m sure you’re in trouble because of something along those lines. If you never ever told anyone the weight ever and they never even saw the scales, than I think you’d be good because it was never used in the seller’s decision process, only yours.
Just think about it completely objectively. Don’t think about how honest you are or how you’ve never ripped anyone off, or how you never tell customers the weights, whatever put that aside, and just think how easily you COULD scam people operating in this way. And, no offense, but not feeling responsible for something on the website of your own business is a little ignorant, no?