I only have corn snakes. I only feed frozen thawed. I'm also a vet tech so I'm more a 'save the small fuzzy creatures' type person. With all that aside, I am not against feeding live for a snake that is only going to take live. These things happen and I'd rather not have someone's pet starve to death. If people are careful, there are going to be very few accidents, but accidents can still occur. My sister-in-law used to work at a pet store and witnessed a rat kill a young ball python by tearing off a large chunk of its skull after it missed a strike. I have a rat snake that was fed live even after he went blind. The previous owner didn't leave the rats in with him for hours, but he still got injured a lot because he wasn't able to aim his strikes. I got him after he got bit in the roof of his mouth. He's 16 years old now and I'm fairly certain he's the snake equivalent of senile. Feeding live to him would not be responsible feeding. One simply needs to be aware of all the potential factors.
Yet another piece of evidence against feeding LIVE !