My honeymoon was arranged by my parents, who purchased everything based on vague instructions (near Carcassone, must have a pool, if I remember correctly). We didn't play any part in it beyond this.
The wedding had about 40 guests, and went very well (it happened to be about the only dry day in a very rainy summer, but thats a different - and less impressive coincidence)
We arrived at our honeymoon accommodation, and got talking to the owner (who was cleaning the pool). It transpired that he had family near where my wife had just moved from. In fact, on the same street doing the same work as one of my wife's friends. When we enquired if he knew her he answered
"Yes - that's my sister"
We told him that she had been at our wedding a few days earlier
"Oh?" He replied "She did say that she was going to a wedding last weekend"
(In short, a completely randomly chosen holiday home, in an area we had never previously visited of another country, was owned - and attended, by the brother of one of the 40 guests at our wedding. With whom she had previously discussed our wedding)