well i have thought of that 2, but thats is really pushing it. I mean if a soldier would make a boot kit, than that wouldn't be suprising, they don't search POW's that good in the field, so... but there are other tricks 2, replace the laces with 550 paracord, you can hide small surgical blades and other small stuff in the flaps of your BDU pockets (cut the cloth of the flap on the upper ( closed position)/ lower ( opend position) side a little bit open, do your stuff in it and sew it shut, make sure it is flexible, thin ( so it won't be noticible ) and washable ), sew small compasses on places were the are normally buttons,etc. If you want to conseal stuff that won't be taken if your kidnapped, taken prisonar or whatever, just take things they proberbly won't take and conseal stuff in it.
but for civilian life, i think it is a little TO much... i mean if that is the only kit you carry it would be nice, but you don't want end up survival kits in your boots, sewn in your closhing, in your pockets, on your belt, in your jackets, etc. ( heavy and annoying if you have to go through metal detectors ) reduncandy is fine, but if you got 6 kits on your body...

if you put the stuff under your sole, you can put some wide cloth like tape over it so that it is harder to spot the gear wenn somebody pulls it out of your shoe. Nice if you are a POW and want to test you SERE skills...