Hey Edie~ I do it just the opposite!! I always stick my hands in the cages of my boas so that they get used to that intrusion on their space. I stick my hands in for cleaning, water changes, getting the moss out to dampen it, and for getting them out of their environment.
Conversely, I only and always use hemostats to feed them. The see that long shiny object coming at them with a great heat signature and fur and WHAM!!!!
Happy snakes!!!
For ball pythons, as well as one boa, I tap them on the head when they are posturing and before they have tried to tag. Tapping them on the head stops their posturing immediately and that's when I scoop them up. I also don't ever put them back into their environments until they are calm and chill; I don't want them associating stressed and squirrely behavior with being put back into their cage