Traffic Accidents: Rear Ended Someone and Accidentally Gave Incorrect Insurance Info

My question involves an injury that occurred in the state of: Florida

My sister accidentally rear ended someone recently. Per her accounts, she and the lady she hit pulled into a nearby parking lot where an officer was already finishing up with another accident. The officer looked over both vehicles and advised he did not see any damage and did not write up an accident report. My sister gave her insurance card to the woman she hit however the card was for her previous carrier Progressive - she currently has Geico. A couple weeks later my sister starts receiving calls and emails from Progressive - apparently the woman she hit filed a claim. My sister is not responding to Progressive's inquiries because they are no longer her carrier (and was not her carrier at the time of the accident) and because an accident report was not written up. I advised her she needs to take care of it because the woman's insurance company will eventually find out her current carrier is Geico and will contact them.

What happens if she just ignores the inquires from Progressive?

Thanks!

Traffic Accidents: Rear Ended Someone and Accidentally Gave Incorrect Insurance Info