Hate to reply to my own post but I wanted to share what I got back from my Netapp account team who researched internally for me.
Got this from our expert
They have to shut down ASM to be safe. In some cases they could just dismount the ASM diskgroups, but they might as well just take that one final step and shut down ASM across ALL nodes on the cluster. There can be ASM metadata in use anywhere in the cluster, so the only way to be 100% safe is shut them all down.