R1 extends arm
 

When the R1 extends his/her arm prior to whistle/signal for serve, the coach must be seated. Is there any other situation where extending the arm has significance?

Libero replacements must be done before the whistle/signal. Substitution requests must be made before the whistle/signal. Same with time out requests.

Am I forgetting any situations?

I suppose make sure the server has a ball in posession and is ready to serve. A few situations where my team was beckoned to serve and server didn't even had a ball nor was even close to end line.

Other situations where receiving team didn't even had six players on court, when a player went to retrieve a ball and now is tying shoe lace off the court.

:D - I got an out of rotation call on a few of those situations.

I have to laugh at the few occassions where wrong team was beckoned to serve. :p

Pay attention ref!