Huge caveat working with Vagrant and Puppet

Never, ever remove the content of the /tmp folder on your VirtualBox:
I have done it today, and after getting a weird warning:

[root@osb-vagrant tmp]# rm -rf *
rm: cannot remove `vagrant-puppet/manifests': Device or resource busy
rm: cannot remove `vagrant-puppet/modules-0': Device or resource busy

I have discovered that all the puppet files on my HOST machine had been deleted... the Vagrant mapping between the Vagrantfile directory on the host, and the /tmp/vagrant-puppet folder on the guest, seems to work BOTH WAYS.
So, just leave those folders alone. I know, it's painful.