Well, I find dangling extremely dangerous. More dangerous than just setting the feeder into the enclosure.
Dangling puts the feeder into panic mode. If you drop that panicked feeder, its going to be extremely scared and the chance of it biting out of fright is increased. Frightened animals are dangerous animals that will lash out.
Putting the feeder into the enclosure gently, keeps it calm. I have never had an incident where the feeder immediately went to attack the snake. 100% of my feeds, they just walk around exploring or just sit and groom themselves until the snake gets them.
Some responsible live feeding tips:
1) Feed the appropriate size food. I like smaller and more frequent meals than larger and less often. Weanlings and small rats are safe and harmless(to some extent). They're also not as conscious to danger as an adult would be. Adult rats can pack a nasty bite and are much stronger at fighting back, which is why "smaller and more frequent" is the way to go. I feed all of my adults small rats once a week. And multiple smalls for the big girls. A medium size would be the max appropriate size for a ball python. Even if the rat was able to bite, a smaller feeder won't do as much damage as a larger one. And another reason I like rats more than mice is because the equivalent size of an adult mouse is the same as a harmless rat pup. Adult mice can be nippy, baby rats not so much.
2) Keep the feeder well fed and hydrated. They're less likely to see your snake as food. Hungry rats are dangerous rats. They will eat your snake if left unattended for extended periods of time. This is the reason for most snake killing incidences.
3) Don't dangle the live feeder. This puts them in panic mode. A freaked out feeder is a dangerous feeder. Gently place the feeder into your enclosure. Calm feeders are good.
4) Monitor your feedings and keep a tool, such as tongs, on hand to assist your snake in case the feeder tries to bite down. Like I mentioned before, I use a chop stick to stick in the feeder's mouth if its in a bad position.
5) Don't keep the feeder in with your snake longer than 30 mins max or so. Some people have a shorter time frame. If the snake doesn't eat within that time frame, take out the feeder and save it for next week.
Overall, it's pretty rare for a feeder to immediately hone onto a snake and immediately attack it unless it was already scared in the first place.