A potential, and dangerous pitfall, is that if a vote involves procedural defect, it is at risk of being invalidated. This is so if any member is denied the vote, though small accidental failures may be disregarded. A person must be specified in advance to announce the ballot results, and unions may not endorse any result of the vote until that has happened. The ballot only gives four weeks' to the union to take action, though this period may be extended with the employers' consent, which is common if collective negotiations are ongoing. If all else has failed, then for industrial action to commence the union must under section 234A(4) give at least seven days notice, accompanied with details of the workers to take part.