Many great ideas and many thanks to the contributors.
The 'Medical Emergency' thread is important to all travelers and every post offered relevent methods and precautions. Frankly, I would do them all in triplicate; instructions in each vehicle, on my persons and on my significant other's persons. I would add a copy with the vehicle registration and maybe even clipped to the visor (not on public display).
Not meaning to be gruesome but the plan should cover a worst case scenario where everyone is unconscience and the EMTs are minimally equipped. They are trained to check wallets and police will check registration. A good samaritan might even check the visor (without disturbing the 'scene'). It is the "Golden Hour" and every second counts; think, plan and then sleep easy.
I agree that the USB device is not a good choice. When have you ever seen an EMT rush to a victum and start booting up his Dell? Maybe in the ambulance (unless you are (both) receiving CPR). Maybe in the ER but I will tell you now that most large networks disable USB because of security risks. The metal bracelet is low-tech, recognizable and indestructible.
A small thing I learned from CSI is cell phone entries. Name them "Wife - cell", "Wife - work", Father, Doctor, Son, etc. so that first resonders can quickly notify next of kin. My phone has an "ICE" (In Case of Emergency) feature that I can program with very specific notes.
My 'gizmo' is a UPS - Uninterruptable Power Supply. Think of them as a surge protector on steroids. A simple power strip with surge protection has a small element called a "varistor" which protects by destroying itself. A generator is a large device that destroys varistors as do funky power drops at the CG. When varistors are depleted you have no protection and you are not notified. I use strips but I write the 'activation' date on them and discard after 12 months. For an RV I would discard after 6 months.
Simple math says that a $100 UPS will protect all of your big ticket electronics (TV, computer, ipad, kindle, cell phone) for 5 years for less that 10 surge strips. Replace the battery and you get 5 more years at double the savings. They are portable so the B&S uses the same UPS and when you press "OFF" there is no parasitic power loss and your equipment is totally isolated.
The battery aspect is irrelevent in terms of watching the late show during a blackout; though you could. The battery is, in this case, the surge protector (blocking spikes of high voltage), the 'brown out' protector (supplementing low voltage) and transient suppression (when you switch from shore to gen to inverter). It does more but it gets techy.
The other "gizmo" is a 'heads up' about LED lighting; it is super efficient. I calculated that you could put one LED every 6 inches over the entire ceiling of a 30 ft. RV and it would take two weeks to discharge a standard 12 volt battery 50%. 300 LEDs use the same amount of power as one standard, 7 1/2 watt home night light.
Yes they have a different hue and, yes they are not going to replace every lighting requirement but they are changing the whole equation. By that I mean that we used to buy based on 'watts' now we buy based on 'lumens' - the actual amount of visable light. Heads up.
For those of you who hang out a strand of lights on the canopy I suggest you spend $10 on a christmas clearance sale this winter and hang a strand of LEDs at the next camp. I think you will find them soothing, non-blinding, more light than you need and, as my DW claims "romantic". "If it's rockin', don't come knockin'" At my B&S I have them strung in the garage, patio and lanai. 6 hours per night cost 2 cents per month.