Absolutely, that is to say that, if a worker says that it suits him that his employer retains his passport or his identity cards, that's his personal choice, and there's no problem. However, that's not how it's presented, because it's a requirement in some cases.
In our community consultation with the organizations, we suggested that the employer instead retain a copy of the identity paper and that the employee keep the original at all times. If he needs his passport—