CITES classification of Womas and others...

[Invictus]

I was browsing the CITES species list, and I noticed that Aspidites Ramsayi (Womas) and Aspidites Melanocephalus (Blackheadeds) were CITES II listed. So why is it that it is supposedly damn near impossible go get these species from the states, since they are in the exact same CITES class as common BCIs? Am I missing something about how CITES works? Is it because it's hard to prove that they were captive bred? I'm wondering if it works this way for other species as well. If anyone can shed some light on this for me, it would be much appreciated.