Originally Posted by
abraxis
Also that PRC requires expen$ive visas for US citizens to enter the country

while HKG does not. ^
There are two reasons:
* Reciprocity
* Supply & demand
However, they are now handing out multiple-entry visas now. So if a US citizen plans to go to China after the JFK-HKG segment, he/she may already have a multiple entry visa.