It has been a while here for me.
Feeding outside of the cage as stated by others really does nothing good. not just with BP but with all snakes. taking them out of their comfort/safety zone is more likely to lead to them refusing, or regurgitating their food. BP's like the safety and security of their enclosures. Most snakes will, when stressed or in fear rather regurge their food then take the chance of being attacked, (in the wild), because they are in a vulnerable state. the whole process takes a large amount of energy for them to accomplish. While a lot adjust and are ok with it. overall there is no "Benefit" in doing so.
as stated prior the chances of them getting accustomed to handling then food could lead to more aggressive behavior that your not wanting to deal with. What i actually do is a few hours before feeding is, i remove all their water bowls, do any spot cleaning as needed, (i use Newspaper so i can 100% tell if there has been anything messy done), i do not feed them with in dirty conditions, and "In the Wild" once they make a mess they move to a different location. then i get my rodents thawed, they are all active and on the hunt for food at this time for me. i feed them, then after cleaning the bowls i put them back in. generally they calm down and realize no more food is being offered.
Good Luck to you with what you decide to do.
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