Hi @sdwannew13 

By default, the Velocloud Gateway will advertise the default route. In our SD-WAN Topologies, one of the most common scenarios is having a Hub-Spoke. If we consider this scenario, you may want to advertise a default route from the Hub to the Spokes to have an "internet" backhaul scenario to send all internet traffic( 80/443)  through the Hub for different purposes (inspection, rules, etc). 

There will be different scenarios in where default route would not make sense to be advertised from the Hub but we need to analyze the topology of your network to provide a more accurate answer.

Let me share with you the link for the Administration Guide VMware SD-WAN

https://docs.vmware.com/en/VMware-SD-WAN/4.5/VMware-SD-WAN-Administration-Guide.pdf

Please let me know if this answers your question. 

MarcoHB