The
entire point of what I’m suggesting is to have a device identify itself.
If you set your phone to randomize its MAC address, then it should not send anything that specifically identifies it. If you ask your printer to connect to your corporate wireless network and you tell it to use WPA4-self-provisioning or whatever it’s called, then it should fully identify itself. Also, it’s a printer, and anyone in WiFi range is presumably privy to its existence.
Sure, if someone else spoofs the network, then they might collect the printer’s provisioning info, but one way or another the printer needs to decide to trust whatever network it ends up connecting to. And with a sufficiently well designed protocol, if the printer connects to the wrong network, then the owner of that network can’t actually impersonate the printer to the real network, because the derived keys won’t match.