The question is whether it would fall under the definition of animal cruelty and whether a prosecution would be likely. I think that is a case would brought it is possible that live feeding of vertebrates could be classes as cruelty. however a prosecuation is unlikely and I know people in the UK do live feed. If the snake will take a dead animal I think that would be a safer option. You certainly shouldn't, for example, video it and put it on YouTube.