Sounds like a good idea on the surface, but the song and dance of scanning a QR to get the unsigned event over to the signing device and then scanning another QR to get the signed event back to the broadcasting device would get old really fast since EVERYTHING you do on Nostr needs a signature from your private key, not just signing in.

Just try using Amber signer with zero automatic signing permissions to see what I mean. And the method you are talking about does not allow for automatic signing of any of them.