The CA law for youth athletes (17yo and younger) is found here:
http://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=124235.&lawCode=HSC.
The relevant section that I referenced is Health & Safety Code 124235(a)(1) which reads as follows:
"An athlete who is suspected of sustaining a concussion or other head injury in an athletic activity shall be immediately removed from the athletic activity for the remainder of the day, and shall not be permitted to return to any athletic activity until he or she is evaluated by a licensed health care provider. The athlete shall not be permitted to return to athletic activity until he or she receives written clearance to return to athletic activity from a licensed health care provider.
If the licensed health care provider determines that the athlete sustained a concussion or other head injury, the athlete shall also complete a graduated return-to-play protocol of no less than seven days in duration under the supervision of a licensed health care provider."
Unfortunately, many treating physicians, even those who treat youth athletes, do not follow the law and many clubs that have made a commitment to better concussion protocols, and may even have published guidelines, do not follow the law. Additionally, tons of refs and on field coaches do not follow the law. Some may take issue with the law and say it is part of the nanny state but it is clear and, in fact, the rationale is incredibly sound (as I think I posted upthread, I am friends with the physician who led the drafting of the mandatory CIF return-to-play protocols and she explained the progression in thinking and the "WHY" behind the 7-day. And that SHOULD START after a player is otherwise symptom free (the law does not require that - just a 7-day protocol - but CIF does and if your kid suffers a concussion, you should insist on strict compliance even as you think he/she seems "fine". Why? Because we are talking about brains and a subsequent concussion in close succession with a preceding one risks a sports career and, more importantly, changing your child's brain in an enduring (sometimes irrevocable) way. (Steps off soapbox)