Ok, so you lock everything away and they never learn to not touch certain things as they could cut, burn, poison them etc. What do they do when they go somewhere and they come across such things, have never seen them before, take more of an interest and end up hurting themselves as they've not been taught not to touch? My cleaning products are kept in a low, unlocked cupboard, but you can't get to them without pulling out a box, which even I struggle to do. C was told from an early age that these things can cause pain, so don't touch and she never has, but she knows what they look like so if she came across them somewhere else she would know that they could still cause pain and would leave them alone. Never letting her see the contents and putting a lock on the door would just fuel her curiosity and make her more likely to try to get to the contents. A lot of kids I know can get through child locks quite easily anyway. I certainly wouldn't suggest leaving chemicals where a child can easily access them though, but you could just as easily leave a bottle of bleach on the bathroom floor when you're cleaning, get distracted by one child falling over etc. and end up leaving it there without thinking, the other child, having never seen it before, wanders in picks it up and drinks it/pours it over themselves etc. etc.
There are sharp edges on tables everywhere you go! I spent most of one holiday with my had across the edge of a marble table that my recently walking 16 month old was constantly bumping into. Do you take corner edges everywhere with you? Accidents will happen regardless of how well protected your home is and as a parent you are responsible for TEACHING them how THEY can prevent the accident as far as possible.
A friend of mine doesn't even use plug guards as they figure that it is more dangerous to use them as putting something into the plug can make it live and if a child then tried to use something to get it out, they're more likely to be electrocuted. I do have some plug guards where the sockets are obviously open, more for friends' kids than my own, but I can sort of see the logic.
However, it does depend on how your house is set up to start with. Some houses will need more child proofing than others. i.e. we didn't have any glass tables and tablets etc. were already kept in high cupboards, we don't use the fire so it doesn't get hot, but C knows it could do and has been taught not to touch it, my fridge is too high for her to get into etc. and knives have always been kept out of reach. I don't have any blinds that they could get tangled in, but C has been taught not to go near the blinds in my parents' house as she could get tangled in them, even though the cords have been tied up high, purely because she could come across then somewhere else and be tempted to play with them.
My attitude is to EDUCATE your children about how to avoid accidents BEFORE they happen (but I do appreciate it depends on the child, as some children really just won't take telling).