That's more of a myth where ball pythons are concerned. As they take a bit longer to look at their prey than say a corn snake, if you don't smell like a mouse/rat and things you put in there don't smell like a mouse/rat, they won't just start striking. I used to feed in separate enclosures exclusively (and still do with my corns) but for my bps, they get fed in their tubs and I have yet to see any sign of aggression or feeding type behavior towards anything but their intended dinner.