It's not just breach of the Netflix contract, it's also unauthorised access to copyrighted material, which is a type of theft, if you are using a friends net flex logon, you are accessing content which the content owner has not given you permission to access.
I am not going to have a debate about the semantics of the word theft, but it is clear that accessing and using or distributing copyrighted material without permission of the owner of that material is against the law.
