I agree with vbroucek- I am sure that most on this board (& CX's where this thread is referenced), find even the thought of what the OP wants / got away with to be incredibly, well: incredible.

I am not sure of the circumstances under which CX allowed you this..but
I for one would definitely protest to the ISM of something like this is allowed around me- and this would surly earn the employee at least a severe reprimand from management (Unless CX allowed to avoid a DYKIA moment)..

So to answer the OP's question- SQ doesn't, and neither does CX- you just got lucky once - time to move on.

Perhaps be flexible with your dates- or book further out - getting 2 seats isn't impossible.