Yet a number of questions arise. First, are these new migrant workers really so flexible and mobile? Second, if they are segregated in the most insecure jobs, is such segregation socially sustainable in the long term, that is, resistant to socialization, but also not feeding social unrest or inter-community tensions? Moreover, is it sustainable for the workers themselves? As the European Foundation for the Improvement of Working and Living Conditions has admitted (Krieger and Fernandez, 2006), mobility comes at big social costs for the workers themselves and their families. And third, what role can trade unions have in this process? Can they accommodate such segregation, as a form of indirect protection of national of national workers’ more secure position, or can they act as a social ization bridge, narrowing the gap between national and foreign employees?