+1John, sometimes the KISS (Keep It Simple Stupid) principle comprehensively beats sophisticated and/or expensive overthought ideas.
Just accept that, despite the best possible D management, going hypo can unexpectedly occur ..... and ALWAYS carry a quick response snack. It can be some dextrose or a mini container of 4 jelly babies, a few fruit pastilles or my current solution the mini-packs of haribo sweets. I am never without something anywhere in the house or anywhere "out" - after a couple of stupid times getting caught out. These days, thanks to alerts from my CGM, I very rarely even go near hypo (never mind actually going hypo). But I still have a mini response pack somewhere close. I had a near hit last week in Aldi, sucked my haribos and problem averted; plenty of choices also from the store shelves - but the answer was in my own pocket!
I carry a funsize pack of skittles in my pocket if I can't carry food in something else, ~17g of fast acting carbs, tastes decent and they conform to my pocket! They do eventually get warm and turn into a congealed mass after being used for a number of days (though I don't carry them all the time only when I think I might need them - i.e. stuck somewhere I can't easily find other food/escape (school plays and the like come to mind)). They are cheap enough to throw away and get a new packet once this happens and even in this state can be eaten if required (in fact rather than throwing them away my children quite like them like this, win-win 😉)