I worked in game retail for over six years, until Game closed our Gamestation. But in all that time the PEGI and BBFC were always treated as law anyway. We could lose our job, be fined £5000, get a criminal record and even do prison time. So for any (responsible) retailer, nothings really changed. (All this was by an external group that would randomly test stores. The same that test shops for selling booze.)
Of course the parents would still buy their child an 18 game and think it was all stupid, but if you explained the content of the game to the parent 7/10 times they changes their mind but 9/10 at least they stopped to think about it. The other 1/10 it was some ass that said their son has seen worse stuff than GTA, Manhunt or Doom in his own home...okay o0...
In the end it's the parents responsibility, they should be the ones that insure their kids aren't playing age rated games. But when the parent isn't around, then the retailer has to pick up the slack, and not allow the kid to buy a game above their age.
As for banning/rating games. PEGI is more fair. The rules and people behind it were thought of with games in mind. BBFC is for films (British Board of Film Classification), they often banned games or gave poor ratings simply because they don't understand the difference between the medium. And you do interact differently with a game than a film.





