A colleague at work has a Note 3, and he's new to the Android platform. I was warning him away from upgrading to 4.4.2 and explained some of the problems we've been talking about.
So he asked how updates arrive, and I explained OTA, and also suggested that, if he did wish to elect to upgrade in the future, he always had the option of downloading it himself.
I then showed him how to access the software update from the settings after the update was released, whereupon he scrolled to the update screen, and the upgrade began automatically downloading.
We tried desperately to abort the upgrade, even removing the battery, but once it rebooted it went into install mode. I didn't realize that downloading and installing the upgrade isn't really an option, it's a statement.
The guilt!! After all my warnings and tales of woe about the ext SD card, I threw his phone to the wolves. Luckily he hadn't installed any apps, and only uses the ext SD for media storage. He's probably over on the Note 3 forum now, complaining about the blockhead at work who screwed up his phablet.