That is where different degrees of non-consent come in. Nobody here is enduring Fritzl levels of abuse, because if anyone who was absolutely unwilling to wrar and violently forced to do so could communicate with the outside world, the cops would be on their keyholder's ass faster than the wearer could introduce themself.
However, many wearers who posted here over the years have been locked as a result of less-than-enthusiastic trades. Between guilt tripping, threatening to withhold common forms of parental care or making offers that most parents would make without expecting a chastity belt in return, there are plenty of ways to create a less-than-consensual keyholding relationship.
Those people tend to love their parent-keyholders despite their dislike for that dynamic. They might depend on support that they are afforded by the belt, but that becomes uncertain when they fight back.
Those arrangements are underpinned by something that is technically an agreement. Describing that agreement as voluntary would however be questionable at best. Giving away sexual self-determination and bodily autonomy under sich duress seems unconscionable to me.
When making such agreements with a random stranger, sure. If the key/belt is the only power the keyholder has over the wearer, securing freedom from non-consent is easy. The devious part is that using those weapons against your own parents can easily mean destroying your previous family life, and that leaves a huge range of consent situations that are unwilling enough to not be valid consent, but not enough to choose the nuclear option.
