@scottmuc would make sense if you're building an app.  But I think a cookbook is more analogous to a gem.  The Berkshelf documentation backs this up - it says Berksfile is equivalent to Gemfile and metadata.rb is equivalent to gemspec.  According to Yahuda Katz's [tl;dr about gemspec/Gemfile/Gemfile.lock](http://yehudakatz.com/2010/12/16/clarifying-the-roles-of-the-gemspec-and-gemfile/):

- When developing a Gem, do not check your Gemfile.lock into version control.
- When developing an app, do check your Gemfile.lock into version control.

Yahuda notes that the Gemfile.lock wouldn't be used to resolve gems anyways, and the same is true of resolving cookbooks with Berksfile.  A semantically versioned gemspec (for gems) or metadata.rb (for cookbooks) is the best practice.  That's why the newest rubygems gives semantic versioning warnings on `gem build`.