Having arrived back from Shanghai last night i can tell you that the current backlog of cargo in China is huge, this has been caused by airlines like Cathy etc etc taking freighters out of service during the slow down, then a huge pre-christmas boom in air cargo bookings.
This has led to freight agents chartering airliners and other airlines also chartering in hardware to try and shift the backlog at a hugely inflated price.
Space is at a premium at the moment so the chartering of aircraft ex China aint no mystery....still makes much better reading to speculate that the freight is illegal arms.