Basically all the network would see would be multiple "instance ID"s submitting work
No. The network wouldn't. It's decentralized.
Each node only knows what it's peer tells it.
Therefore, If nodes 2, 4, 6, and 8 were all connected to each other, none of them were connected to nodes 1, 3, 5, 7, or 10, and ONLY node 2 was connected to node 9, then nodes 4, 6, and 8 would all get the submitted block from node 2 (or from each other). They wouldn't know that node 10 submitted the block at all.