There's a big difference between a legitimate captive breeding program for endangered snakes and a hobbyist simply removing specimens from the wild. Standard reintroduction deaths of captive bred animals is estimated at 90%+ for many and getting that number down requires a lot of work and knowledge. Any reintroductions from a program almost always include the specimens being part of long term monitoring, sometimes via RFID, to see how the animals are doing and adjust for success.