50. Concerted action that curtails services or affects their quality must be authorized in a secret ballot by a majority vote of the members of the recognized association who participate in the ballot.
If the association belongs to a group of associations, such concerted action must be authorized in a secret ballot by a majority vote of the members of the associations of the group who participate in the ballot.
The recognized association must take the steps necessary in the circumstances to inform its members, at least 48 hours in advance, that a ballot is to be held.