The Mediation Service shall conduct each consent election by secret ballot. If at least two labor organizations are to be on the ballot for a consent election, a labor organization promptly may ask the Mediation Service to allow its name to be removed from the ballot. A decision of the Mediation Service under this subsection is final. Subject to any limitation that the Mediation Service sets, each party to a consent election may designate one or more observers to represent the party during the consent election. For good cause, a party to a consent election or the Mediation Service may challenge the eligibility of an individual to vote in the consent election. The Mediation Service shall impound each challenged ballot.