They only request songs for the Getting Ready, Formal, and Highlights b/c the ceremony will be the actual footage of what was filmed that day as well as the reception. This means whatever was playing in the ceremony as well as the reception will be in the video. The only problem with adding music to the ceremony and reception is the duration as well as blocking out the speech part. So if you don't want the actual sound, either your video will have no speech in it w/ just the song playing or you have to go with the actual sound. I think it's better to have the actual sound than to put music over it not only will it look and sound weird but most of your ceremony and reception will be gone (speech/music bkgd) as a result of it.
