A lot of people say this, and it does happen sometimes, but personally I have never really had a big problem, and my first snake is a bp. For all that people say it, I don't really see it too too often. In general if you're getting it from a reputable place you'll be able to ask for a copy of the snake's feeding records, so you can see if the snake has been a problem feeder in the past or not. In general if they weren't a problem feeder as youngsters, they won't really go off feed (missing a meal or two is no big deal) if their husbandry is correct.