When you see people coding in films, such as in Iron Man or The Social Network, where does this code come from? Is it at all accurate?

I have a very limited knowledge of code, but when I see people coding in films I always wonder if they try to make an effort for it to look legit, or just hope that nobody will notice that the code has been stolen from a 'Canadian bank website'.

The BBC has a small feature on the subject today which includes clips and polls if your interested in this kind of thing!