Yeah as long as they don't
you should be alright.
If it is someone that you KNOW, is a friend, is someone in the gaming group's friend and you TRUST this person, you won't have anything to worry about.
In my experience people catch on pretty quickly. I even dumped Eclipse Phase on some super n00bs and they picked it up fairly quickly. Of course I've also had new players who want to kill someone as soon as possible, and then if you react as you would to one of your normal players.. like the police show up... that person will think you're not being fair. JUST A WARNING....CAPITAL LETTERS!
EDIT: Also make sure they sit somewhere next to your most experienced players but not like right next to you, don't want to make them nervous. And of course the experienced player can help them out so they don't need to bother you all the time.
It is also kind of important to engage new players, something you think they can handle. E.g. The Tale of the Nautical Druid. You want them to feel like they're contributing positively, present a welcoming atmosphere, and make sure they have fun.
The most recent new player I had was a I guy that I knew wasn't going to fuck up the game for everyone and wasn't going to be showing up more than just this once. OH AND I didn't know he was coming until a buddy brought him to my house.
, but anyhow, everyone had well established characters and had hired the new player as a Driver. They were investigating werewolves in England but the Driver just stood by the car smoking cigarettes, for two hours (of real time), while everyone else got townspeople angry and killed things.
I could have had some NPCs go talk to the driver, or have the werewolf attack the driver however, It wasn't the full moon, and these townspeople we're getting bullied by the other players. I wish i would've just attacked him, just like some red herring wild dogs or something. He would've had a better time, but i guess some people are just at the table sometimes to "smoke cigarettes" and hang out with people while they play a game.
