Please remember one thing....for all these years I have worked on the orbiters, and since i left the program in 99', the media has got to find a way to hipe up the story line...many times they just get it wrong, mis-quote, or make assumptions....
As to the sensors....I can only tell you in general, that every single inch of wiring, sensors, avionics, and all the systems have redundant backups that run ongoing diagnostics all the time by the GPC's (general Purpose Computers) I believe there are 4 of these on board.....I am sure they would know who, when, where and how long one of the astronauts pass wind!
Bottom line, NOTHING is over looked, and on this mission, they are being extra careful that everything is in the green.....no exceptions...
Obviously 7 lives are at stake, but the whole program will be at risk everytime we/ they launch a Space Shuttle for the duration of this program....tens of thousands of jobs, billions to the economy, FL, TX, and many other states....
The early retirement of the program now scheduled for 2010, has everyone worried about our future employment....the follow on vehicle is still in the design phase, years away from reality.....there will be alot of down time, lost talent before another vehicle will be able to replace this one...
For all her fragility and downfalls, this has been one wonderful machine, a true marvel of mankind....its not Star-Trek, but it is the first steps to get there, the media and the American Public forget this all the time...Space is always going to be an all or nothing proposition......there is no room for errors there......