This is quite deep, and we must think about it from the perspective of the couple and maybe as the couple.
Firstly, if you would even want to nurse this thought; you must be one of the couple's closest friends and most likely on their bridal/groom's train if they are having one. Or maybe a very close relative. If you do not have a close relationship with the couple and you are not sure how they will react, don't do it.
However, if you are close to them; I think you should run it by either party before the day; so, you know if they wouldn't mind.
Secondly, you need to bear in mind that the wedding day is primarily a day to celebrate the love of the newly married couples and in as much as it isn't a taboo to have a new one commence and might also be considered an honor; I think you shouldn't be too selfish to want to do that. Let it be all about them.
More so, a proposal most of the time takes time. The process starts with the man asking, to the shocked silent lady, to everyone waiting for an answer and finally to the celebration of the new engagement. This will automatically take a huge bite on the program lined up for the couple, and they might have to scrap some because of the time factor. Especially for venues that are time-based.
Still, if I am the couple; will I be angry if a distant friend or family member proposes or get proposed to on my day?
I would say No.
No, if it won't cause too much distraction like having your special rented drummers, getting a convoy and all to invade my wedding!!! and all the guests keeps talking about that experience and almost too exhausted emotionally to continue facilitating with my husband and me.
In conclusion, I don't think it's okay to propose at someone else's wedding because it could go wrong. What if she says NO? The wedding almost becomes sour.
Just don't do it.
Photo Credit: Daily Mail