If people want to get into semantics then technically using ANY model outside of the ones on the character selection screen is, to an extent, cheating. You're using an undocumented console command to use a model not available for general selection. The way I personally see it, you can either download new skins and petition the host to copy them onto the server or you can wait for the SDK and people releasing new models. Anything else is, to use a roleplaying term, munchkinism.
'I know you don't see the snipers. Trust me, they're there.'