Vagrant carpetas compartidas y sincronizadas

Creé un Vagrantfile con el siguiente contenido:

Vagrant::Config.run do |config|

  config.vm.define :foo do |cfg|
    cfg.vm.box     = 'foo'
    cfg.vm.host_name = "foo.localdomain.local"
    cfg.vm.network :hostonly, "192.168.123.10"
  end

  Vagrant.configure("2") do |cfg|
    cfg.vm.customize [ "modifyvm", :id , "--name", "foo" , "--memory", "2048", "--cpus", "1"]
    cfg.vm.synced_folder "/tmp/", "/tmp/src/"
  end

end

Despuésvagrant up ovagrant reload Yo obtengo:

[foo] Attempting graceful shutdown of VM...
[foo] Setting the name of the VM...
[foo] Clearing any previously set forwarded ports...
[foo] Fixed port collision for 22 => 2222. Now on port 2200.
[foo] Creating shared folders metadata...
[foo] Clearing any previously set network interfaces...
[foo] Preparing network interfaces based on configuration...
[foo] Forwarding ports...
[foo] -- 22 => 2200 (adapter 1)
[foo] Booting VM...
[foo] Waiting for VM to boot. This can take a few minutes.
[foo] VM booted and ready for use!
[foo] Setting hostname...
[foo] Configuring and enabling network interfaces...
[foo] Mounting shared folders...
[foo] -- /vagrant

Mis preguntas son:

¿Por qué Vagrant está montando el/vagrant ¿carpeta compartida? Leí que las carpetas compartidas están en desuso a favor de las carpetas sincronizadas, y nunca definí ninguna carpeta compartida en mi Vagrantfile.¿Por qué la carpeta sincronizada no está configurada?

Estoy usando la versión 1.2.7 de Vagrant en MacOX 10.8.4.