Wives do have protection against bullying from husbands, they can leave, if it is violent they can call the police. I know it is harsh but society has to treat this carefully, it is a sensitive issue. Australia's legal system, unlike some countries, protects a woman's right to leave and not to be abused. It is up to the woman if she feels her relationship with a controlling husband (or a man with a controlling wife, or a child of voting age with controlling parents, etc etc) is worth giving away her vote, but at the end of the day it is her choice.
I am not sure what protection Max is referring to, if he has some trick I would like to understand it, but when he talks about protection in the numbers game, he might be referring to the statistically small number of coerced votes that will occur. For the reasons I mentioned before serious coercion would be illegal, that creates a risk of incarceration etc if you partake. Subtle coercion may and will happen, but enough to swing votes, probably not in a county like Australia that respects base liberties for all individuals.
Another situation is the dominant member simply takes their sign in details, from then on controls their entire vote. There are so many situations, and whatever protections you put in place on the technical side, you cannot be in every home watching every action. This is a social issue and will require policing.
Another example, a child of eligible age has beef with her father, activates the duress and (depending on what investigative and punitive system you have) accuses the father of coercing her. Flux could take the fathers vote privileges away (maybe I am beginning to understand @christinekent privilege terminology now), but he never did anything wrong. To be responsible you need to rely on police/investigation/legal processes, all too complex and authoritative for Flux to be responsible for, Flux just gives the population the tool to enact effective protective processes.
You could have this but I argue is it necessary. If you get 1 or 2 delegations, it will not be enough to sway final votes. If you get many you will not be able to be sure who has delegated and who has not.
I am not sure, but I assume Flux will allow you to change your vote at any time until the vote period is over