"Nevertheless, politicians, such as Belgian Prime Minister Herman Van Rompuy, who claim that the regularization of illegal immigrants which they are granting today will be the final amnesty, should not be believed. Recent experience shows that amnesties do not close floodgates. They open them. Regularizing illegal immigrants attracts new illegal immigrants."
See : http://www.brusselsjournal.com/node/4025.
Not the most respectable of sources, but even suspect sources can offer morsels of truth.