And well they should. Grand Canyon ranks at or near the top in NP areas in the number of SAR operations per year quite regularly. A lot of it is simply high visitor numbers.

I am surprised no one has mentioned Maxpedition products. They have a lot of sling packs, small to moderate volume, which are more casual than a conventional backpack. I am not a big fan, because to my eye, they are unnecessarily clunky and too laded with MOLLE (or PALS, whatever) loops that increase the weight and aren't that useful. Still, they can be useful.

Maxpedition bags are very well constructed; I have one (Condor) but very rarely use it because while "bomb-proof" it is unnecessarily heavy and stiff. Their small bags which I have seen are made from the same heavy material and are way overbuilt for a small bag you want for casual use. FWIW, IMO

Here's one that might show what you are looking for:

http://m.youtube.com/watch?v=Xnq8iJfBnMs

While not useful, this one is hilarious because the presenter thinks it is a waist pack!

http://m.youtube.com/watch?v=ER00GfF4W2E

The larger version looks interesting but for me this hits the "sweet spot" for balancing size against capacity. It enforces a discipline, which helps counter my tendency to over-pack. And, in an office setting, the fact that it is carrying a tablet computer gives it instant credibility without marking me as a scary "prepper".

Standard disclaimers, no commercial interest...
Steve

Forced discipline ... yep, that's one reason I keep one of the older Camelbak Mules, but with that I have 100 oz of water and room for essentials.

As I see it a tiny pack is step 2, first you need mindset and after that the mind will determine the pack size that's appropriate.

I have a Maxpedition Kodiak gearslinger. Mostly I use it as a laptop bag. It works very well as a bookbag, not so well as a pack. The single strap is fine for short periods but over time it puts a lot of pressure on that one spot. I've found it gets to be too much if you load it down, but it's fine for computer.