Your wedding is the one place where you get to tell people what to wear. Sure, you're not responsible for individually dressing everyone, but you can give them guidelines they're expected to follow. And there are a few biggies, like refraining from wearing white unless you're the bride, and not straying too far from the specified level of formality (black tie, cocktail, etc.) Another less thought-about rule is making sure you don't accidentally look like you're in the wedding party if you're not. Especially if you have tenuous ties to the couple. Photos last forever, and it might give an impression that the couple did not intend to.
That's the situation one bride found herself in when her dad's wife wanted to blend in with the bridal party, despite explicitly not being a part of it. But commenters were split on just who was in the wrong. Read on for the story and decide for yourself.