Your employee handbook is exactly that: the employer's rules for employees. The phrase you quoted is not a valid 30.06 notice. You can get fired, sure; but you aren't at any legal risk.
As for the "knives" issue... how, exactly, do Fry's employees open boxes? Boxcutters, perhaps? Those weapons of mass destruction used by terrorists on 9/11? And the company actually provides them to employees?
Kevin