You probably found out the same way I found out that the hand brake + manual transmission will slow you down and get you home when the main brake line goes out in a 95 XJ haha!
There's a definite pucker factor when that pedal goes to the floor the first time, though.
The PCM just probably runs checks to see if the AC is running, not if it's actually there. Since it's never running, there's no adjustments needed. Now when they plug everything in, the PCM will see it when it runs.