Immigration control in Canada

"Immigration supervisor" is a vivid metaphor. For example, if you want to immigrate, you must not leave the country you want to immigrate for a long time (short term) like imprisonment, because you cannot apply for naturalization or lose your immigration status if you leave for a long time.

Immigration supervision has two meanings. One refers to the time you must live in the country where you immigrate in order to retain your immigration status. The other refers to the time you have to live in order to become a citizen. Immigration prisons are often nicknamed "immigrant prisoners". In fact, an immigration prison is not a prison, and sitting in an immigration prison does not put you in prison. It is only because it restricts the freedom of immigrants to a certain extent that it is called this name.