I feed live as well to everything, and always have.....always will.......live rats are not dangerous unless you leave it in there for hours on end with no food or water.....if you are a responsible keeper, you will have no issues feeding live......as long as you pay attention. Rats have, and will, chew a snake up over time if left unattended.....i would NEVER suggest leaving a live rat in a tub/cage overnight, but like Robin mentioned, if you leave it in for 30 minutes, and it doesn't eat it....pull it out, offer it food and water, and offer it to the snake again in a week.
To me f/t is a pain in the butt....and the rodents SMELL.........BAAAAAAD........I would rather have live rats in the house for a few hours, then frozen rodents thawing in my sink/kitchen/anywhere in my house for hours......I breed rats for my collection, and would rather do that than buy f/t.......just personal preference.
Good luck to you,
Jason