It has got nothing to do with how smart or dumb Apple thinks people are, and has got everything to do with the legal system. Most of the US and the UK fall under Common Law where judges interpret laws and contracts to the letter. If something isn't written in the contract then it isn't there. This in contrast to Civil Law countries where judges interpret laws and contracts according to their spirit. If something isn't written in the contract then the judge can still make a decision based on what is reasonable. This is the reason why US contracts are insanely long: every single stupid corner case, no matter how obvious, like chewing on iPods, have to be mentioned, otherwise you can be held liable.