I'm not convinced that "OFF" means "OFF"

All of my garmins behaved this way. Fully off by long pressing the power button then select the turn off option. When 12V socket gets energized (vehicle on or accessory mode), garmin would turn back on.

So off means off until power is reapplied.

My 3 Garmins all have behaved that way as well.

The sure way to tell if the power is off at the the 12v outlet (cigarette lighter?) is to look at the LED on the power cord. If the light on the 12v adapter goes out when you turn the ignition all the way off and remove the key. Some 12v outlets are on the "Accessory" circuit.

All of my GMC pickups have had "Un-switched" outlets (on all the time). I had to pull the adapter partly out of the socket to shut down the power cord, else there a minuscule drain on the battery.

BTW - I always hold the button down and wait for the message, else it will go into "Sleep Mode" and cause a minute drain on the GPS battery.

Some cars have power sockets that remain live for a period of time after the ignition is turned off. My Ford has a 10 minute delay for example.

I think the comments here are mixing two issues: is the accessory outlet really off? Versus is the Garmin really off?

I don't think the original poster expressed any doubt that the accessory outlet was off nor can there be any reasonable doubt. After all, if it were not off and having it come back on again would not turn on the Garmin.

But having the Garmin activate when the 12 V power connection comes on seems to him incompatible with the being really off. I actually take the opposite opinion. It could be in a more thoroughly off state and turn on in response to power application then it could be and turn itself on in response to a mere pushbutton which is not in fact interrupting the power connection.

Remember power switches that were real switches? That used to be standard. But these days we expect PCs, phones, and many other devices to have a little pushbutton. We push that button and expect it to "power up". But since that thing is not actually a power switch the only way for the computer to notice it and respond is to be not really quite fully off so that the switch is monitored.

Anyway, my answer is that the OPs accessory outlet is really off, and that the Garmin is "as off as it gets".

When one plugs in "power" to a Garmin via a PC USB cord does the Garmin not turn on.. from whatever state it is in. In a similar vein, when the OP turns on his ACC circuit his Garmin will turn on even when it is totally off. Guessing that it is impossible to totally turn off a Garmin that has power supplied to it. Without that feature it would be impossible to charge a totally flat Garmin

"Off" just isn't what it used to be.

What Ralph6410 makes sense.

Actually what I desire is a reasonably simple way to "mute" the Garmin when I don't have a defined destination for navigation. Many years ago I had an early Garmin and if you hit "View Map" in the top right corner was a simple "Mute" button. With the 2689 I can get to a muted device, but depending on the method I have to hit numerous menu items.

Phones used to have a removable battery so you can ensure it's truly turned off (and not spying on you). No such luck any more.

That's the case with lots of things. Unlimited data (cell phone context) used to be unlimited, now it's unlimited up to a certain amount, then it gets throttled (with many providers).

I supposedly have unlimited data with my home internet too. However, i'm sure if I exceed a certain amount I'll get a nasty letter telling me im using too much. Hasn't happened yet, but there have been months where 4-5TB has been used.

Ice cream used to be sold in 2 qt containers, now it's in 1.5qt containers at the 2qt price. I expect a gallon of milk to no longer be a gallon any day now.