I don't know where this tradition comes from, but I did this at my wedding rehearsal. All the bows from my showers were attached to a paper plate and that was my rehearsal bouquet.
Another tradition from my bridal showers was to cut a square of the wrapping paper to use as the background for my scrapbook pages.
One thing that my MIL told me at my shower (after breaking a bow) was that every bow broken while opening a gift equaled one child.
