Because Article 20 of the Labor Contract Law clearly stipulates that "the wages of workers during the probation period shall not be lower than 80% of the minimum wage of the same position in the unit or the wages agreed in the labor contract, and shall not be lower than the minimum wage standard where the employer is located."
Therefore, the service fee given by Company A is lower than the local minimum wage, which obviously violates the above provisions and infringes on the legitimate rights and interests of workers.
This risk is shared by Company A and the labor service company.