Hi Steve,
I have asked in the past if opening the same wallet on a different machine at the same time is bad for the network and I was told that it could corrupt your wallet.
If this is the case, is there any way to block one of the wallets from connecting as to avoid any future accidents?... (Remember.... Grandpa Joe!)
In theory, it should be fine to run the same wallet on multiple nodes. If there is no network lag, the updates on one wallet (e.g. sending coins) will get relayed and the other wallets will update as well. I've never done this for any length of time. The real test is with staking. If two or more nodes running the same wallet are staking, in theory, the first one to stake should get approved and the others will generate orphan blocks.
If you block grandpa's node, he will not be able to keep in sync.
-Steve