IDK how many people are using a computer for a router, most people have a regular wifi router which come on line pretty darn quick. If the WiFi is not available when the HM boots because your PC/Router is still booting, then power cycling the HM after your WiFi is up and running would get you connected back to the WiFi, seems simple enough to me. Also keep in mind, this whole scenario we are running down is based on "what if the power goes out while you are cooking", which I think should be a rare event? Plugging in an ethernet cable should have no effect, as it is not the wifi device, and if the check is only done when the HM first boots up and attempts to connect to WiFi anything you do after the HM is booted would have no effect (would not result in any automatic action).
Again, my suggestion is this... At boot the HM attempts to connect to the Local WiFi, if it can not connect it switches to AP mode (where you can connect directly to the HM from any wireless device). If it doesn't connect to your WiFi for whatever reason at first boot, power cycling the HM would make it attempt to connect to the WiFi again, once it is connected to the WiFi nothing will "automatically" make it change to AP mode ever.
That said, this is just an idea of how we could make the HM more "network friendly', 'cause I really do think you should be able to plug the HM into the wall and then connect directly to it with I-Pads, cell phones, laptops etc, if you have an easier way to accomplish this I'd be on board....