If your friend is stopped and cannot produce proof of insurance, her auto insurance card, then law enforcement would normally cite her for driving without insurance. The penalties for driving without insurance vary depending upon state laws but can include fines, jail time, impoundment of the vehicle, registration suspension and driver's license suspension.

Your friend may be able to get a ticket for being an uninsured motorist dismissed if she can provide proof to the court listed on a citation before the due date however this would likely cause her to lose time from work to go to her insurance company get the documentation that the court will require and then appear at the courthouse to show her proof of insurance.

Depending upon state laws and the courts dismissal procedures she may still be faced with a fine or court fees for not carrying her insurance card in her car and having it in her possession when it was requested of her by a police officer.

Perhaps knowing the penalties and time off work she would have to take if cited for driving without insurance will motivate your friend to find her insurance card and put it in her vehicle so she can have in available for law enforcement if she or another driver of her car is stopped and is required to show proof of insurance coverage. 

If you want to know your specific state's penalties for driving without proof of insurance contact your state's Department of Motor Vehicles.