The best discipline is children knowing that their parents expect something done FIRST time, if asked.
Unfortunately, the majority of parents are too namby pamdy to be able to instil this from a very young age so they resort to smacking, shouting or a long discussion about the incident, which the child usually takes no notice of whatever so ever, as it's usually repeated and they've heard the 'chat' so many times before! ....See mumsnet discussion about the father who couldn't get his child to leave a playdate so left without her and the mother had to send him back!!!
Most parents seem unable to distinguish between fairly mild silly, but normal childish behaviour, and something more serious as I hear them screaming at their kids in the same manner for both!! Choose your battles to fight, I say e.g. always hold hands to cross the road, ignore the silliness as long as it doesn't affect others too much and praise, praise, praise when they choose to do the sensible option.