That is correct. See the description below:
What is Instant Guest VLAN?
Aruba Instant Guest VLAN is a feature that simplifies the administration of guest traffic on a wireless network. In it, guest users are placed in a controller-assigned internal VLAN, and guest traffic is forwarded by the AP to the virtual controller. The virtual controller then source-NATs all of the unicast guest traffic onto the wired network.
How does it benefit the customer?
It greatly simplifies the configuration and administration, both on the wireless as well as the wired network. For example, if you have a mix of employee and guest traffic, and the employee SSID is set up so that users can get their IP address from the native VLAN, then the switch port need not be a trunk port. From a wired network perspective, switch administrators can thus assign all of the APs ports as access ports.
Also, since the guest VLAN is internal, it created automatically, and the Virtual Controller always assigns non-conflicting IP addresses. Broadcast and multicast traffic is dropped at the AP’s Ethernet port, and Proxy-ARP and DHCP relay all help reduce unnecessary traffic on the network. There’s less configuration needed on the wireless side, and the wireless guest network planning is completely transparent to the administrator.