It would also make the following thigns very difficult:
-screening those passengers, given that TSO's aren't travelling
-dispatching flights given that flight OPs/GAs aren't travelling

I'm not trying to be sarcastic (ok...not entirely), I'm trying to make a point about people in general using more specific language when they discuss things like air security/safety.

On a more practical note, this is actually a bad idea when used to 'combat terrorism'. The point of terrorism is to disrupt as much as it is to kill. Thats why 9/11 was so successful. Now we have taken to solving that problem by creating huge pileups at airports in the name of security. It honestly surprises me that no one has attempted a serious terrorist attack ON a check point line on a monday morning at a major international hub like IAD, JFk, LAX, etc. That would likely cause something like you suggested to be implemented. The end result of THAT would be that not only are the lines now worse, but it means that the lines are now outside. Think about the effect a car/truck bomb would have on a large group of people standing at the curb waiting to get into the terminal.

The point of all this is two fold. First, most of these calls for extra security are ineffective because of poor execution of security and poor intelligence operations which are what creates security holes in the first place. Plugging ineptness with more hassle isn't a solution. More accuracy, more accountability, and more common sense need to be applied. Not only is this important from an annoyance standpoint, but when the poicies you have in place fail because of people, more policies can't solve anything.

Second, many of these security measures actually put the traveling public in a lot higher danger. Lets say you have a 1 in 1 billion chance of being on a plane attacked by terrorists. ATL had almost 1 million flights out of it last year. Something like 2500 a day. Thats >100 an hour. The odds of you being exposed to a terrorist attack at an airport, are therefore roughly 100 times higher (obviously this is ghetto math). And, it would likely be more succesful especially at this point in time because more people are there waiting at the checkpoint. Further, think about the pyschological impact of attacking the security checkpoint. No longer will people be made to feel safer by the TSA, they will feel under threat the entire time they are at a checkpoint. The chaos between the TSA and the traveling public this would cause would be spectacularly self destructive on all sides.