There's an even simpler, more effective way of checking blind spots: Actually turning ones head and looking over the shoulder. The "blind spot" doesn't exist when drivers exercise proper caution and responsible driving behavior. Of course, expecting this of drivers is unrealistically utopian. Nevertheless, a "blind spot" is just another excuse for unsafe drivers.
The method in the article doesn't eliminate the blind spot, just puts it in a place that's easier to see.