No, you should not be liable for this accident. The legal owner of the vehicle (your father) would be responsible regardless of whose tag was on the vehicle. The legal owner can be determined by contacting the Department of Motor Vehicles in your state. You should contact your insurance company and speak to a claims representative to let them know what happened so that auto insurance fraud is not committed. They will to respond to the claimant (the other party) that you are not liable since it was not your vehicle. The claimant (the other party) will most likely try contacting your father and will find out that there was no insurance on the vehicle.

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