Little children sneak screens because the pull is strong and the limit feels arbitrary to them. They are not being deceptive in a morally sophisticated way. They are doing the only thing available when something they want very much is off-limits and they do not yet have the language or reasoning capacity to negotiate. The sneaking is information about the desire, not about character.
I found you watching. Let's talk about what happened, not to get in trouble, but so we can figure it out.