That must be Bobby Droptables twitter account :-)
I still don't quite get how this doesn't work. Why are they handling "NULL" as a special case? What's coercing "NULL" into null?
I.e., if the value looks like JSON, it will parse it and return the object tree, otherwise it will return the original value as a string?
This sounds like a horrible idea in general - I'd say the authors of this forgetting that certain english words by themselves are valid JSON is a nice cherry on top but hardly the worst problem caused by this.