a human sitting down or the pack of ice cubes in the freezer??? None are moving so which will they bite? It's not the ice cubes so I will give you one more guess
Boas strike based on movement to the best of my knowledge not
heat. I've got a little guy who's het for snow who will strike at
the glass over and over if he smells a rat. The glass is cold.
So how do you remove a boa from the cage without moving, hell you may even become rich off the idea, start mass producing your invention and some people MIGHT buy and others will use the frozen bottle of water. Do you own retics? Prolly not so you need to "hook train" them since they are very aggressive feeders you need to let them know when you open the cage that is not feeding time so the hook will touch them several times.
Your statement again
Boas strike based on movement to the best of my knowledge
since this true tell everyone who is feeding f/t and just leaves the rodent in there over night and miraculously it is gone the next morning and the snake has a noticable lump but in reality the snake didn't eat the rodent cuz it didn't move, so the rodent came back to life and jumped in the snake's belly which happens thousands of times a day too so go figure
just my thoughts on your comment
heat.
Bob