It is an excellent point. My current BOB, SAR 'Ready Pack', and backpacking pack are one in the same. A 60L hiking pack (which I leave space in for the unexpected, 'wife gear' or group search and rescue equipment)...though I tweak the contents and layout for each task a bit.

In some posts I've made recently I've been trying to find tactical gear in yellow for SAR...but putting in perspective what Iron Raven points out, this is bad for the same reasons. If you have to bug out you want to blend in and bright yellow gear head to toe is just as bad as camo. If you're trying to get out of Dodge and every 2 blocks you get stopped and asked if you're an EMT or disaster relief...or mugged for medical supplies, you're no better off.

My pack might be a bit big but where I live downtown you see people walking around with heavy packs all the time...travelers staying in hostels, the homeless, etc. However right now my pack has a Gerber LMF II and a Gerber Brush Thinner Machete strapped to the outside...there's no way I would leave it like that to walk around in the urban jungle.