This is what
the rules for CX actually say:
For all classes, each passenger (except an infant) can bring a free baggage allowance of one cabin bag not exceeding 56x36x23cm (22x14x9 in) in size. These dimensions include wheels, handles and side pockets.
In addition to the above allowance, you may carry onboard the following items free:
* An overcoat or shawl
* A small handbag
* A briefcase (no more than 4kg or 9lbs in weight)
* A notebook or laptop computer (no more than 4kg or 9lbs in weight, including case and accessories)
* A small camera or a pair of binoculars
* An umbrella / walking stick / crutches
* A "forward facing" infant car safety seat for ticketed child (aged between 6 months and 3 years) or infant bassinet or cot (that can fit on fold down shelves and can be properly secured)
* Infant food and nappies (for consumption in flight)
* An infant collapsible pushchair (if cabin stowage is available)
So a standard size carry-on, PLUS a briefcase, PLUS a laptop bag, PLUS a handbag is perfectly acceptable by the rules.
Moreover,
in addition to that, First, Business and MPC of Silver or above in economy can carry on "One garment bag not exceeding 20 cm (8 inch) thick when folded in half, or one soft bag not exceeding 20 cm (8 inch) thick*" (the * being unless you are going to, from or through LHR).
So in total many passengers can legitimately carry 5 bags onto the plane.
I do note though that the cabin baggage rule for KA does seem to be simply "one bag" (
http://www.cathaypacific.com/cpa/en_...p/mpo/benefits Note 11) so there is a HUGE difference between CX and KA in this respect.