It's not that it's not possible, it's just that it's extremely rare. I've seen Natalie's photos also.
Is it a fluke? No. The vast majority of these animals don't even make it to breeding age and those that do are usually in no condition to breed. There's no reason to expect that as people being keeping these animals more competently, more CB babies will hit the scene.
There have been scammers all over the place selling what they claim are CBB exanthematicus. The point is that 99.9% of the savs sold in this country are WC and loaded with more bugs than you can shake a bottle of panacur at.
In the meantime, with the exception of the isolated events, there is no reliable source of CB savs in this country. No one is supplying the pet stores with a yearly clutches of CB savs - they are almost always WC and the CB birthings are so rare that people make a huge issue out of posting pics of the clutches in order to avoid being called out.