With the exception of the visor, you can't make players transparent.
You couldn't be further from the truth. They are just looking at it the wrong way.
%client.hideNode("ALL");
You can replace ALL with the nodes amade said, but if you want to hide everything use ALL. It has to be capitalized too.
%client.unHideNode("ALL"); would unhide all nodes, but impractical.
To restore a client to visibility I would use
commandToClient(%client,'UpdatePrefs');