This is (sorta) what Capistrano runs:
~$ rvm_path=/usr/local/rvm /usr/local/rvm/bin/rvm-shell 'ree' -c 'cd /path/to/project/current; echo $BUNDLE_GEMFILE'
/usr/local/rvm/config/Gemfile
This is what happens if I do it myself:
~$ cd /path/to/project/current
/path/to/project/current$ echo $BUNDLE_GEMFILE
/path/to/project/current/Gemfile