The tempting answer to “do you see this device?” is to scan the LAN, search hostnames, and call the result. That is useful only when the thing is actually a network participant. It says much less when the device is attached by USB, paired over Bluetooth, asleep, or visible only through a vendor app on another endpoint.
The sharper rule is to inventory the layer that can observe the truth. A router table can show network clients. A host can show its USB bus. Bluetooth needs local radio visibility and pairing state. An app may be the only place a workflow device exposes itself at all.
That distinction prevents false confidence. “Not found on the network” is a receipt about one layer, not a verdict about the object. Good operators say which layer they checked, what it can and cannot prove, and what access would be needed for the next check.