That's not quite right. Out of my 5, one does this, my little mojave. He's a picky eater. Only eats about every second feeding or so. If I fed live, he would get bitten for sure, I have to drop it in and leave it there and I have to be about 10 ft away before he will even think about it.
You should also attempt the "zombie dance.. I put a towel over half of her aquarium and stand behind that.. Even still, as soon as I put it in the top, she grabs it right away.. I also wiggle the prey a bit while she's constricting it as well to give the feel that it's alive.
Just my opinion.