On my development machine:
$ bundle exec rails console
Loading development environment (Rails 3.2.3)
1.9.3p194 :001 > Rails.env
=> \"development\"
RAILS_ENV is a variable like any other which will always default to development
if you like you can always open up '~/.bash_profile' on the production server and add this:
alias sc="bundle exec rails console production"
then run source ~/.bash_profile
to reload that file for your terminal session and you can just call sc
to load up console.
The rails executable can't know which environment should run on which machine.
you can put export RAILS_ENV=production
in your ~/.bashrc
or ~/.bash_profile
file of the user you want to start the console with.