Probably not the right venue for a deep theological discussion, but ya, don't you give the right answers in tests? Like if it was a test of faith about God's existence in an atheist society, the right thing to do would be to proclaim "God exists". But here, the test is to pretend that the lie is true to everyone else, but in your head, to know that this isn't the right answer?
In this moral framework, I wonder what the right ethical thing to do when another creationist is the customer? Do they both accept the lie^H^H^Htest of faith?
It's a test of personal faith, they don't have to proclaim it to others to 'pass the test'. They pass the test by having faith without proof.
It depends on how they interpret the results to the customer. They might show the data and say that "it seems that this rock is million years old". They don't have to believe it themselves.
If the customer is another creationist, they probably marvel the perfection of God's creation and how impeccably he has been able to fake the age of the universe. You know, they probably see it as an evidence of God's omnipotence.