Why can't my daughter wear her earrings?

Jewelry of any kind, including earrings (even if covered with a band-aid or tape), are not permitted while playing soccer.  Jewelry can cause injury to the player and/or other players during the match.  Referees will not tell you that you have to take the earrings out, they will just tell you that the player cannot play with them in.  The parent is responsible for deciding what they would like to do at that point.