Everyone would be well served in this industry if we chilled out a bit.
I always check in, but am surprised at how many times i've been told by Captains (from Airtran to Delta) that if you have a seat in the back you don't need to check in. Seems odd to me but like everything in life, your mileage may vary....
So lets everyone chill out and be more agitated by the smurf stealing your flashlight at security than a poor guy sitting airport reserve for 21 bucks an hour who is trying to get home to see his woman, kids or pet water dragon for a couple days a week.