Hello again, Angel.
To answer your question, no there is no law which requires you to report the accident to your insurer. However, if there are any injuries or the vehicle damage is $1,000 or more, then it must typically be reported to the police and the DMV
. Since this does not appear to be the case, and you did stop immediately, it does not appear you did anything legally wrong.
Here is a link which summarizes the law with regard to accidents:
However, because one of the drivers is now alleging that he incurred damages and could potentially file a lawsuit, you may wish to report this to your insurer if you have full coverage since they would normally have a duty to defend you if a lawsuit is filed. This would typically save you the cost of attorneys fees. Ultimately, the driver asserting the claim should not prevail since there appear to be plenty of witnesses to testify as to what really happened, but you could be saddled with significant costs and fees if you must defend yourself in a lawsuit.
I hope this helps clarify the situation for you. Please remember to rate my service once you have all the information you need. If you have any other questions, please ask me – I’ll be happy to respond. Thank you!