I feel funny about asking this question but a recent debate with my brother and friends forces me to solicit outside opinions to settle the debate. FYI we are all US born citizens and had no prohibited items or excess dutiable items. Flights were from Cozumel, MX and we were reentering the US through IAH.

This past weekend I was traveling with my wife, 2 y.o. son and my brother (35 y.o.). My brother wanted me to put him on my customs form as part of my family. I didn't think that is what 'family' meant so I told him to fill out his own form. I thought he was just being lazy but he told me afterwards that he wanted me to do this because a single man traveling from Mexico would be a "red flag" and make him more likely to be searched which I said was ridiculous.

My questions:
Can anyone with the same last name be put on one customs form or is it more appropriate for him to travel as a single traveler and fill out his own form?

Is traveling as a solo traveler really a red flag? I can't believe this because that would mean that about half of the people I see in the customs hall would be under suspicion. It would seem to me to be a very unreliable indicator.

Thanks for your feedback

Keba