@Sasha's mom brought up the idea. Sasha is the one who is hesitant.
Sasha To be clear though, she brought up the subject and is ok with the idea.
It makes no sense to accuse her of pushing her mom to wear a belt out of jealousy when she isn't pushing her mom to wear a belt.
Andrew The fact that one person in the family started wearing a belt should not oblige anyone else to wear it.
Of course it doesn't, but it does mean that other people in the family know that chastity belts exist and what's involved in wearing one, and are more likely to think about wearing one.
Damien As are belting rules that are enforced on selected family members only
In @Sasha's case, we're talking about self selection. Sasha had a problem, her mom offered a solution, Sasha accepted the offer and finds that it works for her. Why should someone else with a potentially different set of needs be obligated to adopt the same solutions? Why shouldn't different people in the same family self select different solutions to their different needs?
It seems to me that it's okay for two different people to make the same choice if they want to. I think it's also okay for them to make different choices.