There is no guarantee that a BP that has been fed live will not eat f/t on the first attempt.
It becomes an issue over time if the snake continually refuses and begins to lose body condition.
I have never had a live feeder that I could not trick to eat f/t (with enough work).

Dirty gerbil bedding is especially great for scenting f/t rodents for the BP with discriminating tastes...

Best of Luck!