Although we have a KEK and DEK code for regular VMs, they are not operative on GHA...yet. The reason has to do with a technical conflict with copy-on-write we aim to close, not least of which because Ubicloud needs to grow its own copy-on-write features for block device snapshots, things we lack today.
I expect within a few months, all expired GHA vms will be cryptoshredded upon their deletion. This is already true for regular virtual machines or managed postgres machines.