The story came from people who believed that since snakes are animals of habit, they would get conditioned into thinking that opening the cage meant food was coming. This was debunked years ago. There are some snakes which are territorial with their enclosure but that has nothing to do with feeding. As long as you interact with your snake and stuff, you should be fine. All my gals perk up when the cage is opened but the minute they smell my hand and not a rabbit or rat, they lay back down and I pet them, change water and usually take them out. I have used hooks for any of them, I just reach in and pick them up and they are fine. The problems came when you have something like a retic or burm who have very strong feeding responses. Then you try and move them into a feeding tub and feed them. Then you try and move them out, yeah not gonna happen as they got long feeding responses.
Also some people didn't like to feed in cages if they have them all decorated and feed live as the rodents will run around and could hide in stuff and you don't want to leave a live rodent with the snake unattended. Plus rodents will pee and poop all over in the snakes cage. I feed prekilled and F/T so the only problems I encounter are aspen on their food. I cure it by using paper plates or a big ceramic casserole dish I got that I plop the snakes head and food item onto and they usually eat it there.
My BP girl has been on a hunger strike now for about 3-4 months now, since Oct or Nov. I don't really remember as I don't pay attention. I just try a rat on her every 2-3 weeks when I feed my yearling sunglow boa. If she takes it, then I have to get my boa food, if not, well then there is no waste as my boa gets it.