I think it's probably fine and 99.999% of people wouldn't bat an eyelid, but honestly, I wouldn't bother and would find something without a white background. It's the only colour you have to avoid, and I tend to be overly cautious with not upsetting a bride on her wedding day, just incase she is that 0.001% that care. I have also been at weddings where I have heard quite bitchy comments made towards a guest in a white background dress, which must have been quite uncomfortable for them.