How did you know it was for Ivy Bells though? The Wiki article describes the huge amount of secrecy around the project; so why did they trust you/your co-workers?
It's called need to know: If you read "Taking of K-129" - about a related - but even more secret op, you'll find countless examples of individual contractors who had to be fully cleared into the program because they were smart enough to "connect the dots".
The result there is they get briefed/cleared in, rather than kept on the outside where their curiosity might blow things up.
