I like Gary's thinking on this. Heck, even a good sturdy "Pocket knife" would work.
I believe one should, when on "Walk about" ALWAYS carry at least two knives. A "Good sized" (What ever that means to you) fixed blade on your belt or pack and a smaller one (Also hopefully a fixed blade) possibly around your neck on a break a way lanyard/chain.
A Little Paranoia Will Keep You Safe (ALPWKYS) Be a Sheepdog JYD#105