To be fair, I hadn't read the script in detail when I wrote my post, just far enough to see there was a definition of a sudo function. On review, it looks like they either call it to chmod/chgrp HOMEBREW_PREFIX (sometimes), or run sudo to create the directories.
The main homebrew page says, 'run this ruby script'.
The ruby script is available at: https://raw.github.com/mxcl/homebrew/go
The script includes a sudo command.
To be fair, I hadn't read the script in detail when I wrote my post, just far enough to see there was a definition of a sudo function. On review, it looks like they either call it to chmod/chgrp HOMEBREW_PREFIX (sometimes), or run sudo to create the directories.