While I agree that a live mouse isn't at the top of the danger/problem/hazard list for captive snakes, I still feel that it is an unnecessary risk.

Early in my snake keeping days I left a mouse in with a ball python overnight despite being told by numerous people not to. The next morning I discovered a snake that had about 1/10 of its scales/skin chewed off. the snake died about 2 hours later.
talk about feeling like a total moron... I know of a few other well respected folks that had the same problem too... I believe one involved an indigo... what a nightmare.

I just figure, why take completely unnecessary risk? Granted, I've only had somewhere between 1000 - 1500 snakes (including babies) in my care which is a fraction of what some people have, but I've never seen a snake that would only take live animals. Also, in the wild a snake would have the option to get away from a mouse that poses a problem, in captivity that option is taken away.
So why chance it?