First and foremost, workers signing a union card to join a union is an indication they want to join the union.
To add a second layer is only to allow the employer an opportunity to interfere with the decision of the workers making that decision in the first place. There is no justification for it. There's no evidence suggesting that workers who sign a union card somehow are not giving their true or authentic indication of whether they want to join a union.
We have had this system in place in the federal jurisdiction for decades. It's never been proven that somehow this will interfere in the democratic rights of workers to choose their union. If you don't want to join the union, you don't sign a union card.
The board, the CIRB, which testified prior to Bill C-525 when the bill was before the committee, indicated that there has never been any contradiction between workers signing a union card and that when there was a vote, the level of support or numbers were any different. As a matter of fact, the indications are that the level of union support went up, not down, in the first place.