Imagine a human starship on a long way home sort of journey, like Voyager, (I'm resisting the temptation to link TV tropes here). The ship approached by a friendly rubber-head alien knows all about the crew and their exploits. The alien expects to join the human crew on their return trip to Earth.
Turns out that human starship is a victim of unscrupulous alien TV network that has its agents on space stations, plant hidden cameras on unsuspecting, interesting looking ships passing through their space. The network broadcasts the ships' adventures as reality TV, and makes lots of money selling ads and merchandise. Our friendly naive alien, who doesn't understand how the scam works, has won a lottery to join the journey to Earth in a ship that is useful to the humans. The human crew decides to keep him and his ship as this will facilitate their trip home.
What kinds of conflict could arise between a human crew and alien crew member who knows all of their secrets of the past year? How will the psychological stress of constant surveillance affect a human crew on a long journey home that could take decades?