I couldn't agree more. I always Carly carry my knife with me, a stupidly sharp high carbon black folding blade about 4" long. it's well used for opening boxes and cutting various twine sticks and the like, it's used and worn but will fly open with just the right flick of the wrist (i lend it to coworkers they can never figure how to flip it open like I can) seriously in under 2 seconds I can have my knife pulled out open and rdy to use for whatever.
twice I had it on me while I was getting robbed. the first time was a group of ppl and I'm not dumb so I gave them my smokes small amount of cash I had on me they were a Lil pissed so I quickly offered up my meds (well sought after) they happily accepted them then got all friendly offering to wait at the bus stop with me become it's a tough area lol.
second time was a Lil 16yo kid. asked me for a smoke I told him no... he very nervously looked around and let slide a piece of broom handle from his sleeve.. then said ok I was trying to be nice, now give me everything. I could easily see he was more scared then I was so I said ok let me get you my wallet, he quickly looked around again while I was grabbing for my wallet then looked back to see my knife in his face... sooorrryyy was all I heard as he dropped the stick and ran away. looking back I definitely would not have done the same thing again. I had 10 smokes and like 40 bucks on me that's not worth anytime in the hospital or worth seriously hurting a desperate kid for.
they are a tool to help you work faster and better. they may make you feel safer but in the long run you really are not. use common sense stay in well lit areas and if your in a rough area (my whole city Lol) have your phone out and be on it telling the other person exactly where you are. ect . my s5 has a 3 click emergency message. turns on GPS microphone takes a pic from front and back and sends it all to my emergency contacts. I feel much safer with that then i would with a machete.