According to Ted's Note Book on Sky after Monday's running, all of the cars have to be legal on track and comply with the rules. (though I would assume aero vanes, speed monitoring equipment, camera's etc would be allowed). Ted said that when Kyvat knocked the nose off his car Red Bull wanted to continue to run some miles just to get a bit of engine data, to that end they had to ask the FIA delagate at the test if it was ok to run the car without a front wing beam. The rules were checked, nothing found that said you can't run a car without that bit, and out they went.
I guess you could set the car up so that it ran too close to the ground and therefore wouldn't pass a scrutineering check and the car still be legal but the question is, why would you want to do that when you know there are a number of things not right with your car and you need to get the maximum legal data out of it while you can?