Responsive mobile theme is not in this scope. Here is talking about dedicated theme for mobile devices.
Acquia cloud is using Varnish. For theme switch solution, it has a problem.
Here is Acquia documentation for mobile: Enabling device-based redirects
And another one about back to desktop version: Circumvent mobile redirects with a desktop cookie
So in my understanding, it requires us to give a different mobile domain, usually subdomain like m.yourdomain.com to your mobile version.