Recruitment Policy - at the time of joining they have taken signature of resignation, full and final

Some industries recruitment policy is not compliance as per human resource. I saw at the time of joining they have taken signature of resignation, full and final and kept in record.they can terminate any employee without any prior notice. Is it acceptable as a human resource department?

Illegally one can do whatever he wish to do; Question is how much time one can save himself from Law Enforcing Authorities.