If you're the
other person on that account: yes, this is definitely a risk, and if you think you co-account holder may soon have judgments awarded against them you should lose no time in disentangling your financial affairs and ensuring that your share of the money is transferred to an account in your sole name. (But
only your share of the money — if it looks as though your account is being used to shelter the judgment creditor's money and protect it from enforcement of the judgment, then you're right back in the mess that you're trying to avoid.)
If you're the creditor: this is not straightforward, and enforcing your judgment against a bank account (joint or single) wouldn't usually be your first step, because there are easier steps to try first.
You can't just walk into the judgment debtor's bank, slap a copy of the court judgment on the counter, and demand all the money. To chase somebody's bank account you can either
- ask the court to give you an order (called a "garnishee order") addressed to the bank, ordering it to pay to you any money that it owes to the judgment debtor; or
- ask the court to appoint a receiver with power to operate the judgment debtor's bank account and use it to pay you what you are owed.
It's not automatic that the court would grant you either of these orders — they might want you first of all to try more traditional methods, like sending the sheriff round to seize and sell the judgment debtor's goods, or just bankrupting the judgment creditor.
Bottom line: A judgment creditor can chase a bank account, including a joint bank account, so co-account holders should be aware of this and take steps to avoid getting caught up in it, if they can. But it's not a common way of enforcing a judgment debt; it's relatively cumbersome and other enforcement methods are usually tried first.