I would think it's a sensible default, but you're right, you should have the option to change it. I actually assumed the option was there, but I just checked in 9.3, and it's not.
But if we can't make the behavior more intelligent we will probably have to add an option.
In that case the checkbox should just be not displayed at all.
Created https://gitlab.com/gitlab-org/gitlab-ce/issues/34248 to track.