>The Employee agrees to devote full-time efforts, as an employee of the Employer, to the employment duties and obligations as described in this Agreement.
The template linked above also an option of specifying work hours, so that makes it extra risky from a legal point of view.
That is beside the point. It's expected you will bring your best effort to the job and not do half-ass sloppy work. The article is not recommending you work 16 hour days, they are recommending you bite the hand that feeds.