Elemental Cage Airship

Elemental Cage Airships are nasty.
"Galvanic Cage" ?
They use captured galvan to navigate their ships. using a spherical cage that looks kind of like an orrery to direct captured galvan. Smaller than Dwarven airships, and without their construction - usually not an air combatant so much as a mobile boarding platform from which to jump off and attack ships.
What does this do to the captured Galvan?

idea 1. it's a traumatic state of bliss. Galvan typically experience divine rapture in their elemental form. being trapped in this form feels great in the moment, but afterward they are left with 'the blues' (x) / wife-from-inception. feel nothing in normal form and just need to jump.

idea 2. it's non lethal torture. painful. the cage disconnects them from the divine experience they normally have when jumping. painful but not lethal.

idea 3. it wastes them away and there's a limited use time for a captured galvan.

Why doesn't this always get met with Galvan judges?

idea 1. something about the cage hides the captured galvan. needs an explanation for why the CREW and the structure of the ship aren't seen. and i guess that requires an explanation for how the Galvan see the world.

something else on the ship hides them. anti-divination magic. or some kidn of anti-galvan scrying circle. like enochian wards in supernatural.