To get back on subject, I am by no means "big man on the block" However I have taken in 3 rescues. Each one of them the owner told me they would in no way take anything but live. I would take them home, thaw out a rodent and the critter would eat it if not on the spot by the next morning.
My last BP rescue was fed live for 7 years, first try with me and he at f/t.
My brother has a ball that he told me time and time again would not eat anything but live, no matter what. I went over there with a frozen rodent, thawed it out and put it in the tote with his ball. Right away this ball started "killing it" and later ate it.
What I am trying to say is, 1%, perhaps, but I would say less than 1%. I am in no way exposed to everything that most people on this site are exposed to, but IMO what is impossible for one is very possible for another.
Never have I see a critter that honestly would not eat anything but live.
And on a personal note, I love F/T, I would rather get a rodent out of the freezer than go to the pet store every day.