I've seen this done at bridal showers, but not rehearsals. I was recently at a shower where the ribbons were stuck to a paper plate, which the bride then wore as a hat. (It was cute actually - one of the "ribbons" was a long piece of white tulle, so it looked like she was wearing a veil.
) This was an Italian family, so maybe it's an Italian custom?
The bride has to unwrap every present herself, without help. She can't use scissors, box cutters, etc. on the wrapping paper or ribbons. The superstition is that for every ribbon she tears, she will have a child. (So her mother and mother-in-law, or anyone else, deliberately ripping the ribbons wouldn't count.)
We did this at our engagement party (I didn't have a shower). I was very careful... if the superstition holds, we will have no children.
