Corrected entry: At the end of the movie, during the wedding scene as Susan is walking with her father down the aisle toward Arthur, the song being played is not the "Wedding March" (a/k/a "Here Comes the Bride". Instead, the celebratory music is being played which is always played after the completion of the marriage ceremony.
Corrected entry: In the beginning of the movie, Arthur is pulled over in his Batmobile by two police officers. A female in the next scene checks her phone and sees a picture of Arthur getting out of the car, however, there was nobody at the initial scene with a camera who could have taken the photo.
Correction: Wedding songs are chosen at the discretion of the wedding party. I haven't been to a wedding in well over ten years that used any of the traditional music at all, so it's hardly surprising to me that they'd used this song at that time.
Phixius ★