There is an easier way to do this without modifying the ghost blog code. Hopefully the developers will leave this method open. I feel very trongly that the ability to disable the members function should be an option, and truly hope that they will reconsider their stance on the matter.
Anyway, you can disable the member helper by running this query in the ghost database:
update settings set `value` = 'none' where `key` = 'members_signup_access';
The method you use to access your database depend on if you are using mysql or sqlite3. After briefly reviewing the code, I do not think that there are any side effects of doing this if you do not intend to use the members function.
I do not understand the rationale behind the decision to force this upon users. Yes, I know that I’m free to fork the project and add this feature and perhaps it may come to that. Not everybody’s goal is to build subscriber lists and send out newsletters. It may be hard to comprehend if that’s where you make your living, but many people do this sort of thing for fun, or use it as a showcase of their accomplishments. These people have no need for this function.
I am personally asking the developers to reconsider their decision.