As a knife nerd this is my least favorite question as it tends to be asked by dipshits that think a knife is going to help them take on 4 guys john wick style in a fight( its not they are gonna take it and stab you to death for trying) i use folding knifes as they were intended. As a tool. I open boxes, cut ropes and ties at work, ect. A knife isnt going to do you any good in a fight especially if you are not trained in kali or something similar and judging by you not knowing the laws its pretty clear that you havent been trained. So TLDR a pocket knife is the worst form or protection i can think of and if you are really that scared to walk at night either dont, or bring a bat so then at least you’ll have range