What if the employee signs a waiver of privacy at the time the start work and are allowed to use their laptops and their network?

 What if the employee signs a waiver of privacy at the time the start work and are allowed to use their laptops and their network? 

Bennett-Alexander, D. & Hartman, L. (2015).  Employment law for business (8th ed.). New York: McGraw-Hill Education : Employment Law for Business, Ch. 14