Not without a court judgment and even then exemptions will apply to protect some property.
If you found this answer helpful, please let me know by clicking the "Mark as Helpful" button or "Best Answer" at the bottom of this answer. Although I'd welcome an attorney/client relationship with you, my comment here does not create one. Our firm is a debt relief agency. We help people file for bankruptcy under the United States Bankruptcy Code.
An unsecured creditor cannot repossess or put liens on real or personal property unless they file a complaint, serve the complaint, and get a judgment. If your friend gets sued, they will know that that process has started. It is quite rare, even with a judgment, for an unsecured creditor to try and force repossession, but the creditor does have the right to attach to property once they have a judgment.
Keep in mind, also, that certain property maybe exempt from being taken by a judgment creditor under California law. I would suggest speaking to a local attorney if the debt becomes a judgment, because this area of law can be complex.
I agree with the answers given by my fellow lawyers. A creditor cannot obtain pre-judgment attachment orders on consumer debts. The creditor must file a lawsuit, serve it on the debtor/defendant, obtain a judgment and then it can record a judgment lien and obtain writs of execution to have the sheriff levy against any non-exempt property. Your friend will have plenty of time and notice long before any assets can be seized. A properly filed BK (7 or13) can trump the creditor's lawsuit at any stage. Feel free to have your friend contact me or any AVVO lawyer offering a free consultation if more information is needed.