I agree with this. A wedding exists to celebrate love and happiness. I could never be upset at someone bringing additional love and happiness to my celebration of love and happiness. People who are have missed the point of a wedding, I think.

If they're an asshole about it and completely take over the wedding with it, sure. But that doesn't really happen. Your wedding has an invite list, everyone you invited came here to see your wedding, presumably they aren't all itching to go see this other extra proposal/wedding that cropped up out of nowhere.