Most wallets are a collection of addresses. These addresses are not intrinsically linked to each other, and simply knowing one address in a wallet does not let someone deduce which other addresses belong to that wallet.
I've had a question in my mind for a long time: Can someone somehow figure out the other BTC or ETH addresses of a ledger wallet?
Let me explain: Imagine someone gets 10 addresses from his ledger nano S, and he uses some of those addresses. Now, if someone else knows that address 1 belongs to that guy, can he somehow figure out the other 9 addresses belong to him? Does ledger themselves know? Can the government know about it? Can a hacker or a skilled programmer figure it out somehow?
And obviously I don't mean the simple case where they share transactions. They don't have any common Tx'.