Moms wearing the same dress?

I feel like all these little wedding problems are coming out of nowhere, and these are the most odd issues, that I never thought I would come across. We stopped at my FMIL's house the other night and she showed us her dress. Today my mom comes knocking on my door...and my jaw dropped..she was in the same dress, same color and everything. Neither one of them knew what the other one was buying, it just kind of happened that way. My mom is wondering if she should change her dress. It does have a sheer jacket, I suggested that she get a different jacket, in silver, since thats our other color, but she doesnt seem to like that idea. I dont think that it will be that terrible if they wear the same dress, but she seems to think it will make for awkward pictures and to make it better, the dresses are non returnable. I dont know what else to tell her, any ideas?