Oh, god. Another survival "expert" touting the use of a tourniquet.

The bandanna looks like an interesting idea - I own a space blanket that has similar survival instructions printed in black on an international orange background. It's a bit small (22" x 22") to use as a sling, though - the standard triangular bandage is typically 36" on each short side. 22x22 makes for a 30" long bandage - about the length of my arm. I once demonstrated to a group of high school students how you could use a man's shirt as an improvised bandage, and was surprised to discover (I should have checked it first) that the sleeve of one of my old shirts was just a smidgen too short to function as a bandage. (It won't go around my upper arm twice - and I'm no Charles Atlas; and it will just barely wrap around my thigh.

If the bandanna were the size of a regular triangular bandage, I might be tempted to buy one. But as is, I'd rather go to the fabric store and buy a square yard of brightly coloured cloth from the remainder bin.