[bastawhiz]

It's easy enough to store sensitive data externally (e.g., in a key value store) and simply store a reference to the data along with its hash in the ledger. When data needs to be removed, delete the data from your KV store and add an entry to the ledger noting that it was removed.

But you probably wouldn't store sensitive user data in this kind of database anyway. Not ever use case is well-suited for a ledger like this. In most applications, this would be pointless overhead.