On Ubuntu 16.04, the default behaviour is definitely to copy it, and there are no tricks with hardlinks or anything else:

    $ virtualenv foo
    Running virtualenv with interpreter /usr/bin/python2
    New python executable in /home/administrator/foo/bin/python2
    Also creating executable in /home/administrator/foo/bin/python
    Installing setuptools, pkg_resources, pip, wheel...done.

    $ ls -la foo/bin
    total 3464
    drwxrwxr-x 2 administrator administrator    4096 Dec  4 11:06 .
    drwxrwxr-x 7 administrator administrator    4096 Dec  4 11:06 ..
    -rw-rw-r-- 1 administrator administrator    2082 Dec  4 11:06 activate
    -rw-rw-r-- 1 administrator administrator    1024 Dec  4 11:06 activate.csh
    -rw-rw-r-- 1 administrator administrator    2222 Dec  4 11:06 activate.fish
    -rw-rw-r-- 1 administrator administrator    1137 Dec  4 11:06 activate_this.py
    -rwxrwxr-x 1 administrator administrator     252 Dec  4 11:06 easy_install
    -rwxrwxr-x 1 administrator administrator     252 Dec  4 11:06 easy_install-2.7
    -rwxrwxr-x 1 administrator administrator     239 Dec  4 11:06 pip
    -rwxrwxr-x 1 administrator administrator     239 Dec  4 11:06 pip2
    -rwxrwxr-x 1 administrator administrator     239 Dec  4 11:06 pip2.7
    lrwxrwxrwx 1 administrator administrator       7 Dec  4 11:06 python -> python2
    -rwxrwxr-x 1 administrator administrator 3492656 Dec  4 11:06 python2
    lrwxrwxrwx 1 administrator administrator       7 Dec  4 11:06 python2.7 -> python2
    -rwxrwxr-x 1 administrator administrator    2341 Dec  4 11:06 python-config
    -rwxrwxr-x 1 administrator administrator     230 Dec  4 11:06 wheel

This is with virtualenv 15.0.1.