Hiding

I wonder what age you have to be to realize the following items need to take place for an effect Hide-n-Seek experience:

1. You shouldn't be in physical contact with the person you are supposedly hiding from
2. The person you are hiding from shouldn't be watching you go into the hiding spot, or see you pulling the blanket over you
3. Something covering just your head does not hide your entire body
4. Hiding in the same spot 5 times in a row is not the most effect method

Again, not sure at what age these things begin to sink in...but I do know its not 4.