I do not have sufficient proof to back up what I am saying, but I can tell you that I have been told of such goings on. People have told me that they had worked for three months and that, a few days before the end of the prescribed period, they were laid off, to then be hired back a week later. They have maintained that they are not alone in this situation, and that it is even common practice.
On November 28th, 2006. See this statement in context.