More suggestions for the KidSafe program (see part one):
"My younger siblings all flip with joy when I run it - "Let's go see if we can break KidSafe!" - and the subsequent keyboard-pounding makes me wonder if it would be more economical to let them destroy the desktop icons instead of the keyboard."
In security, its all about considering your attacker. In the case with children, they have unique weakness: a low tolerance for boredom/frustration. Unfortunately, if a program presents a challenge, their determination may increase so you must destroy the challenge by either making the reward suck or make it seem there's no progression towards a goal.
The honeypot idea:
Give kids an actual desktop with actual icons to play with and move around but they don't do anything. They can change things, but those changes are temporary and nothing actually works. They play around a bit and then they move on because its boring. It seems like they got somewhere but their success is either not real or dull because many features are disabled, including network access and programs.
This is somewhat like what DeepFreeze or Returnil do, but less involved. Its just a fake desktop.
Increasing difficulty idea (requires durable keyboard):
User must answer a few questions. For every question answered right, the number of questions decreases by one, but for every question answered wrong, the number of questions increases by five! Not only that but the right answer doesn't seem to work!
Any minor setback will make kids less willing to work toward their goal. Its a problem videogames have been trying to solve for years: how to increase difficulty for the player without making them feel like they're being punished when they make a mistake. The more it seems like a chore and the less you feel a sense of progress to your goal, the less patient you become. Adults have this problem too, but far less than children.
Additionally, you can make even correct answers appear to be increasing in difficulty or give seemingly negative feedback even when they get the correct answer.