How do I use the "owner" option for deployment?

I am trying to set up a development deployment that will only be pushed if the branch is owned by a particular user, not by another user who pushed commits to a PR.

Here is my circle.yml:

    branch: /.*/
    owner: GeoStrategies

This looks to be correct by the docs:

You can also optionally specify a repository owner in any deployment subsection. This can be useful if you have multiple forks of the project, but only one should be deployed. For example, a deployment subsection like this will only deploy if the project belongs to “circleci”, and other users can push to the master branch of their fork without triggering a deployment:

However, when I push a commit to a PR (from my fork of the repository), it triggers a deployment, which isn’t what I want. It looks like what’s happening isn’t in accordance with the docs? Or, maybe I’m just not understanding correctly how the owner option works. Any suggestions on how to get this working?