It's simple, isn't it? If you don't want to watch your children (or don't have the time, whatever), you shouldn't have them in the first. Sorry, but additional regulation isn't necessary, just because some idiots are shitty parents.
Hell if anything, the rating system is too stringent. What's with the AO rating? Boobs? Dreadful, and your average 17 year old has clearly never seen them, and never ventured into the dark recesses of debauchery that comprise 80-ish% of the internet. No need to be prudes and exclude nudity and sexuality as well, just saying. But that's for another time/thread...