I have a Tucano Second Skin for a mba 13. Fits like a glove and includes a sized microfiber clothe for the keyboard when the laptop is stored in the sleeve. I go through TSA checkpoints four days a week at airports all over the US and leave it in the sleeve with no problems. As long as the laptop is by itself in the sleeve they don't care.
I just got a vinyl skin from Dbrand and put that on my laptop and then just take the laptop out when going thru TSA. Never had an issue with them and got thru troublefree. I have found it is much easier for me to place my laptop out of the case in their bin rather than some careless TSA agent who will just take the laptop out and throw it into the bin...
I find it hit or miss whether or not TSA wants my MBA out of the neoprene sleeve I use. Fortunately with the Pre lines you can leave everything in your bag.
They may be, but they're also regular, everyday people just like you and me trying to make a living. Don't bash their job until you've walked in their shoes. I can't even imagine what it's like to work at the airports dealing with thousands of different personalities every single day; many who are rude, mean and downright demeaning. I've stood in that TSA line and seen folks berate TSA for absolutely no reason. It's a rough job people; don't judge TSA until you've done their work for a week or so.