Angelina I agree that the wearer's needs are a priority here, however the primary role of the keyholder is to be allied to the belt and to the idea of preserving the wearer's chastity.
Yes, the point of having a person to hold the key is to allow for some form of intelligent assessment of the situation, otherwise you might as well throw the key away, so a keyholder has to be present, responsive, and sympathetic.
But by definition the primary role of a key holder is to hold the key!! - They must do everything reasonable, safe and consensual to ensure that chastity is maintained.
This is what I'd want from a keyholder anyhow: Strength with sanity.