That one smells like an urban legend to me!
it does, but at the same time, you have to remember that they once lost a probe to Mars because they had two different groups working on it, one that used imperial measurements, the other used metrics.
My source (the prof) was one of the people who worked on the system, so while it might be a tall tale, it doesn't qualify as urban legend. It was being passed on as a "this is what I saw" not "this is what some other guy saw".
Basically, the point was that the guys in charge of calculating weight (for fuel, etc.) literally had no concept of a system component that had no weight. So they're acting like "I don't care how insignificant you think it is, I've got to know exactly!" -- thinking that the software developers were just being stubborn.