Hey I made this account just to write this comment because I believe I found a duplication exploit.
Spoilers for Alissa's route
During Alissa's Chasity event (when she is wearing the belt near the end of her route) you can leave the hideout and go to New Ark and if you already have Fawn's Chasity event unlocked you can still partake in the event despite not having a Chasity belt on you (Alissa is still wearing it)
Fawn will not acknowledge this fact however and the event will play out normally you will be wearing the belt as usual and when the event finishes (completed or failed) you will get your Chasity belt back (again, despite not having one when the event began) after which you can return the Cassie's hideout and finish Alissa's Chasity event and after that you will get back the belt that Alissa was wearing.
At the end of this you will have two Chasity belts. There is no way to remove the duplicate nor is there a way to further duplicate more belts (that I know of)