I believe we always allow the creation of the proxy for nil; `allow_message_expectations_on_nil` simply configures whether stubbing something on a `nil` prints a warning or not.

At least, that's what the docs say:

https://github.com/rspec/rspec-mocks/blob/46c1f9c819a919a964a4f5fb78771cbbf4d1b982/lib/rspec/mocks/example_methods.rb#L46-L50