If I was able to learn the little English that I know, it is because I worked hard to learn it. The same goes for immersion schools. People can do what they wish, but if people are not given the change to practice French, they will not be able to learn it. It is through speaking that one acquires a language. You should be very familiar with this, you yourself have learned French. It is by practising that one learns the language.
In fact, it is Air Canada which has taken away from these people the chance to practice their French. They don't do it anymore.