Will call of RPC with mode "RPCMode.All" affect all players or only players those have networkView calling the RPC?

Second option. NetworkView is synchronised among the players with NetworkViewID. RPC sends NetworkViewID of calling object along with the call (this is actually based on experience, I don’t know any documentation supporting this statement). When message is received, application finds NetworkView with matching ID, then searches for RPC function with matching name. Therefore, if player doesn’t have networkView with matching ID (which is the issue you are concerned about, as I understand your question), it won’t receive RPC call.