It all depends on the interviewer. I would suggest you write it down anyway.

There is never a fixed process. As an example (non-GE), I entered US with my mother-in-law, a Canadian years ago. I only filled one custom form. The immigration officer asked if my mother-in-law was residing in the same household as me. I said no, and he said we should have completed two forms, but allowed us that time. Last year, I flew in with my mother-in-law again. I completed two custom forms (I wasn't using GE because of my mother-in-law), and the immigration officer said you needed only one and tore off her form. So... it is up to the officer in charge if there is any grey area.