How does Sticky Fingers work: must you hold a resource type, and does it work with an empty Stuff?

Question

Accepted Answer

On your turn, Sticky Fingers lets you take each resource from the shared supply instead of your Stuff. You do not need to hold that type already, and an empty Stuff does not stop it. It does not apply when following.

Fort

How does Sticky Fingers work: must you hold a resource type, and does it work with an empty Stuff?