Ability to suppress "Error-prone config" warning

I've started receiving an error message saying my git config is "error-prone", after moving the .git folder to a non-standard location:

For the repository the .git-admin directory is not located below /Users/xxxxx/.git, 
but at /Volumes/xxxxx/.git instead.
This indicates an error-prone configuration and will most likely result in confusion 
and strange behavior. You should re-clone the submodule from scratch.

I'd like to be able to suppress this warning - I moved the .git folder deliberately and as my least-bad choice.