No, this is illegal.
In our experience, most companies are sophisticated enough not to resort to intimidation. However, company lawyers will advise managers to make statements that spark fears about strikes or tough bargaining by the employer. While it is illegal for any company to fire or penalize an employee who wants to form a union, most employees feel more comfortable if union organizing occurs without the company's knowledge. The company will find out if the organizing drive is successful since the labour board will order a vote.