It seems `find_files` is going to [return all versions of gems installed](https://github.com/opscode/chef/blob/24dc69a9a97e82a6e4207de68d6dcc664178249b/lib/chef/knife/core/subcommand_loader.rb#L102-109) (and it seems [not in any sensible order](http://tickets.opscode.com/browse/CHEF-3151) so we can't rely on rules redefining themselves).