"output directory cannot be in the recipe directory." makes for bad defaults

[benmoss]

With this recipe in a folder, I run rattler-build build and get this error:

rattler-build build
Error:   × The output directory cannot be in the recipe directory.
  │ The current output directory is: /Users/bmoss40/workspace/rattler-build-stuff/output
  │ Select a different output directory with the --output-dir option or set the CONDA_BLD_PATH environment variable

This seems unintuitive since I didn't tell rattler-build where to put the output directory as far as I know. If the default is to put it in the current directory, why is that invalid?