Small children are surprisingly adept climbers, and ingenius problem solvers when the problem is one you don’t want them solving.
Locks with the key somewhere they definitely cannot get it work, right up until you forget to lock the cabinet one time. Then you hope that curiosity doesn’t overcome the bounraries you’ve laid down.
Debian, installed without systemd as per the wiki. So far I’ve not hit any issues, whilst I’ve recently ended up diving through both kernel and systemd code to find the root cause of an issue I was hitting on one server. I could have just bodged past it, but I wanted to actually understand what the issue was, and what else it was going to affect.