ending a TeX region

[Joe Corneli]

  (setq tex-trailer "\\end\\s-*{document}\n")

This might be more of a TeX question than an Emacs question, but at
any rate, the default above appears to fail to be useful for
generating a dvi file whereas my modified version below allows
tex-region to work as expected.

  (setq tex-trailer "\\end{document}\n")

Anyone out there with crossover knowledge care to tell me what is
the meaning and/or point of the default?