Say that persons A and B have a joint bank account, with A as the primary owner, and assume that A gets sued. I understand of course that all funds in the account are exposed in the suit even if B had nothing to do with the law suit. My question is whether other assets of B are at risk by virtue of B’s financial association with A in this account.
Merely having a joint bank account with soemoen does not make one person responsible for the other person's debts or obligations.
However, a financial association of the kind which leads to a joint account may also involve liability for some of the othet person's obligations. For instance, a very common reason for having a joint account is when two people are married. Being married often involves mutual financial obligations, but not because of the joint account. Another reason for having a joint account is if the people involved are in a partnership. Partners are all liable for partnership obligations, but are usually not liable for the obligation of another partner that are not part of the partnership business.
In short it depends on why the joint account exits. merely having such an account will not make one liable, but what ever relationship caused two people to have a joint account might also involve shares liabilities, but not just because of the joint account.