This should not be disabled by people who are not sysadmin as they will end up loosing the admin interface which is not desired for new users. Better solution is to keep long and difficult password (For strong password validator you can open new issue).
For people who are familiar with command-line and are sysadmins, you can disable the admin interface by these command.
yunohost service stop yunohost-api
yunohost service disable yunohost-api
This topic was to stop the redirection to admin interface from the sub domains which are not yet registered from admin panel. Not for disabling the admin interface.