I would be happy to give it a try. Would your example reflash the sonoff device to turn it into a native web thing? or go through some other gateway addon? Ideally Sonoff and other commercial Wi-Fi (or wired) devices that support IP comms would be sold with native web thing support.

For this test I don’t care if I need to hard code a Wi-Fi ssid and password into the Sonoff device firmware.

Ultimately though, for commercial devices, it would be nice to have a universally recognized and broadcast ssid/password that all native web things default to looking for when they are unprovisioned. (The ubiquitous “provisioning channel” would be isolated and all network traffic dead-ended to the AP that is broadcasting it.) The temp connection would be enough for users to “find” new IoT/WoT devices and authorize them (or not) to obtain secure/private network credentials.