First of all, what the heck's the big difference?! So what if kids are playing games? Most parents will buy 'M' rated games for their kids already; does it REALLY matter if they need a parent or not? It's the parent's problem if they don't know what they've bought for their kids, unless they're trusting, so I really don't see the big deal.
Second of all, why do they believe that fining them is going to help? It's like Prohibition in the 1900's, people will still sell 'M' games to underage kids like drugs, alcohol, and porn; making something illegal makes people do it more. Please note I'm not against making a fine and games rated 'M' more restricted, but games are like the alcohol to the gamer's alcoholism; this could seriously backfire!