By default when you install a volume license version of Office 2010 it will not ask for a product key. All Office 2010 client VL builds are pre-PID’ed with a single global product key. When you install Office 2010 VL without a product key it automatically enables Office to seek out a KMS host to activate against.
You may want to deploy Office 2010 VL with a MAK key however. When you deploy Office 2010 VL with a MAK key you may find that on first launch a user gets the activation screen like so.
You can attempt to avoid this screen by automating the MAK internet activation by adding the following line in the config.xml
<Setting Id="AUTO_ACTIVATE" Value="1"/>
Activation success will depend upon the internet status of the machine. Naturally if the machine (or the user that does the install) is not connected to the internet, or proxy info for that user is not setup correctly during the install the automatic activation attempt will fail.