Slightly OT but I fly SIA to Oz. I always book direct with them on their website and (as I'm sure you know) SIA's flights to Oz are always chocker. When you book your seat on their seating plan, even if we book 9 months in advance the a/c is almost always nearly full, in all classes. Does this mean that agents are block booking sections of seats?
As an aside I looked at 380 suite availability on our next flight in a couple of weeks. They were full; so I kept advancing the booking as far as I could and I couldn't find an empty suite seat. Which I thought was odd.