It seems that the current behavior when rvm automatically switches Ruby versions is to do it silently if it's by .ruby-version or, if it's because of a Gemfile, display that three-line warning about how Heroku does it too and with instructions on how not to show that warning again.
I think .ruby-version switching the Ruby version silently is not great, because it requires that the user remember
A simple bash approach to providing automated dependency installation and ruby compilation for the requested version and flavor, supporting ruby, jruby, rubinius, truffle ruby and mruby.
It seems that the current behavior when rvm automatically switches Ruby versions is to do it silently if it's by .ruby-version or, if it's because of a Gemfile, display that three-line warning about how Heroku does it too and with instructions on how not to show that warning again.
I think .ruby-version switching the Ruby version silently is not great, because it requires that the user remember