Shut up about 72 hour clock

I quite like Grady, Bill is growing on me but I am so sick of the 72 hour clock thing. I am sure they have been told to do this because it is now part of the opening sequence. Every episode they say, "under these conditions the 72 hour clock does not apply here" If it does not apply then why mention it.

I am guessing the producers are trying to attention and a sense of urgency to the show but it does not work. We all know you need food and water to survive.