What's so stupid here (beyond the fact that F passengers should ever have to pay) is that other airlines have a way for FAs to activate the system on a per-passenger basis. I think it was Virgin America I flew with once and as a non-F passenger with a pre-paid entertainment option, the FA slid a credit-card-like object through the reader and activated the system for me.
I'm waiting for a credit card reader on the oxygen masks; I always thought Ryanair would be first, but now I'm not so sure.