I don't think it's ever ethical but sometimes the results trump ethics. If you have a hostage situation and mind-controlling them is a hell of a lot more reliable than trying to shoot them or talk them down then you would be a fool not to. The hostages lives are worth more than a breach of ethics and violation to the aggressors freedom. I doubt the hostages would be willing to lay down their lives so you can make a statement about freedom.
Long term changes to a person rather than an emergency response? that's different, I find this to be worse than just jailing or executing them. A grey area with this is if the person was willing to undergo mind alteration as it is their choice. A very very uncomfortable grey area that would depend heavily on the whole situation is mind-controlling a politician or influential figure to prevent a war or violent riot but I lean more towards no with that.
Regardless of intent anyone having this power would be terrifying.
Long term changes to a person rather than an emergency response? that's different, I find this to be worse than just jailing or executing them. A grey area with this is if the person was willing to undergo mind alteration as it is their choice. A very very uncomfortable grey area that would depend heavily on the whole situation is mind-controlling a politician or influential figure to prevent a war or violent riot but I lean more towards no with that.
Regardless of intent anyone having this power would be terrifying.