“Only Customers who purchase a Business Select Fare and Rapid Rewards A-List, and A-List Preferred Members are eligible to use the Fly By Lanes. Customers who wish to upgrade to Business Select may do so through the Fly By Priority Check-in Lanes at the ticket counter; however, family members or other Customers traveling with Business Select Customers, A-List Members, or A-List Preferred Members are not allowed to piggyback with Fly By-eligible Customers.” (Emphasis mine, source)
With that said, before I had Pre-Check, my wife accompanied me thru the Fly By Security Lane 100% of the time, and no one ever questioned us. If you bring a larger family through, your results may vary, and, of course, you always run the risk of your “extras” being turned away since, officially, the benefit is for the A Lister alone.
Additionally, we use the Fly By Check In Lane all the time as a family, but that is a little different since while SW (at the counter) recognizes we are all on one reservation, the folks at TSA may not or may not care.
I’d love to hear your results if you try it.
-A List Preferred, Companion Pass holder, Community Champion.
I too have had luck getting one other person through the fly by lane when only one of the two has status. I highly doubt TSA cares who uses the lane, and most of the time I have used it the lanes merge at the ID check point so as to make it impossible to tell which line you came from. Yes, you will inevitably irritate someone in line for "cheating" the system.