More questions? More answers.
When I add an authorized user to my account does it matter for the credit score which card gets used each month?
No. You don't need to swipe on the authorized user's card in order to help them build credit. Using the primary card is enough.
If I add someone as an authorized user to my account which is blacklisted by Chase can that cause my account to be shutdown?
Yes, it's possible. Chase will sometimes link you two together based on the AU and shut down your account. Bad friends are no good.
If I'm an authorized user on a card do I need to spend on it in order for it to help me build credit or only the primary?
It's enough if the primary uses the account. Your card does not need to be used.