I have a story to illustrate Adam’s point about sequential passcodes. We used to have an Amazon Fire TV which made purchases way too easy. After my then two-year-old accidentally purchased a few things, I set a simple “1234” purchase passcode to prevent that. I made it simple because I didn’t want it to make legitimate purchases a big hassle. Flash forward a couple of years and I found my then four-year-old buying stuff because he had figured out the 1234 passcode.
The lesson: if a four-year-old can figure out a 1234 passcode, anyone can.