Back to the ethics. Unless we are not able to prove we are worthy of keeping salamanders (and we can prove this by breeding) then we should not be keeping them. There are species which can be bred within the xth generation (like Axolotls) without any problems.
I have until so far never have seen any proof for inbreeding problems in newts. Needing new blood is more a feeling than that there is real proof. Far more often it is bad feeding, or bad circumstances why animals will fail to grow or not breed properly.
And since internet...it should be fairly easy to make contact with people and exchange ways of keeping.
But..I must agree that if you don't know the exact locality, you can easily mix up species (because in the past they weren't species and now they are..). This has happened with Triturus species in Europe. So collecting animals in the wild has some advantage. And I think that most of you (like me) would only tkae a few animals, juveniles or eggs from nature if we would go to collect some. The trade however, will collect all there is to collect. Sadly if talking about laws, there seems to be no middle way for private people like us. I think a good system would be to forbid all commercial trade in WC and only allow CB to be traded. To get CB you will have to get in contact with experienced breeders and those experienced breeders (which should have some kind of qualifications) should than be allowed to get a permit to collect WC for new blood or for species which have died out in the hobby. They may however only sell a F2 generation (else they will collect WC that will breed the same year). Of course there is a danger when money gets involved but I think if animals get bred by specialist you will get healthy animals with less damage to wild populations.
But...I am just dreaming, this world is just interested in making money, so traders go for it, not in newts and salamanders. But I still hope that people like you can make a difference.
Sad to see that even in species that are rarely in captivity there is little interest. The same is going on in Europe. Most European species are protected, and keeping is only allowed with papers that prove that they are CB, but there a species which are more trendy than others, and because of that they can die out in captivity. And if we loose them there is no legal way to get them back in captivity because collection permits are only given out for scientific research (and keeping and breeding by hobbyists is not scientific enough...yet).