From the desk of Brandy Buell at CYSA.
In order for an AYSO team to participate in a Cal South tournament this is what is required:
Player registration form/medical release.
Player card.
Team roster for Travel with all proper signatures. 
Application for Travel with all proper signatures. 
AYSO allows teams to participate in non-AYSO tournaments with permission as stated- but individual players are not allowed. If they are to play as a guest on a team, they need to register with Cal South and be covered by your insurance. A non-AYSO tournament cannot be defined as an AYSO-sanctioned event, which is the condition under which our players are covered by our medical insurance.
If you have further AYSO related questions, please feel free to e-mail Margie at margieclose@ayso.org.