to try and stay on track of what people have said,
p platers have 4 points, which if you lose 1 point you get it back 12 months from when you lose it.
people with their opens have 12 points, and you have your points renewed 3 years after you lose them. if you have your opens and lose all your points and decide to hand your licence in for the given period rather than go on a good behaviour bond, when you get your licence back you go onto your p's for 12 months before you get your opens back. my mate is currently taking this route, but it was a pain as he had his motorbike opens as well, and since they are on the same licence he couldn't ride his motorbike as it was above the restricted engine size of p platers.
now if you get caught speeding 20kmh or more over the limit then you don't really have anything to bitch about. you must have been consciously doing that speed. fair enough you may feel cheated if you have just come into a 60kmh zone from a 80kmh zone you would think they would give a few meters to let you slow down, but the law does say that you are supposed to have slowed down to that speed before you enter that speed zone.
double points/double fines do exist. it isn't just public holidays, it is only over certain periods, like xmas and easter, when most people have holidays. i know people that have been booked during this time and recieved the bigger fines.
as for the extra demerit points lost if you get caught speeding twice in 12 months, i think the way they are doing it is a bit crap. it should only be 1 or 2 extra points.
now i don't have a perfect driving record. i have been booked twice, once for speeding 82 in a 60 zone (back when 15-30kmh over was only 3 points) to get home before a hail storm hit. the other time was for undue noise (i accidently chirped the wheels slightly taking off from a set of lights). had i known i was going to get done i would've atleast tried to make it worth while.
but i know that if i speed and get caught there is no point getting pissed off at the cop, or anyone else. i broke the law. i knew i was breaking the law and i still did it, so i have no-one to blame but myself.