Also considered a type of Metagaming.
A: (So.. your character is a viking.)
A: (Your flying a space ship, and you arent human. You do realize that this is a scifi game and humans are thousands and thousands of years away from being vikings.)
B: (Still a viking. Brought my character over from x game name here)
A: (*sigh* Thats Roleplaying cross over, you know.)