Not sure how it works in MP, but the preload series of commands is used in SP at least to preload cutscenes and the like, thus minimizing lag and texture/lod popping. The commands used are
camPreload and
camPreloaded. So something like:
_camera camPreload 60;
waitUntil {camPreloaded _camera};
and it'll wait for a maximum of 60 seconds for the scene to preload for everyone (the scene prepared by _camera, I'd imagine, so just put that in front of the camCommit).
Wolfrug out.