People who are looking for full time work are not freelancers. Typically,this degree of non-commitment by the potential employer boils down to taking advantage of the job seeker's desperation. That week of "freelancing" comes with opportunity cost of searching for full time work.
Of course applying a 10x multiple of employee hourly costs to the free lance period makes it more like freelancing and eliminates a perverse economic incentive toward the employer to use such a scheme for discount freelance services.