Rear brakes do very little on scooters, 80% of the stopping power is on he front discs...
sorry to call you out buddy, but i call bullsh*t
having recently experienced this myself recently, rear braking is EXTREMELY important. i had never previously locked up my front wheel before, but recently on a long trip i had gotten almost home when the person i was following slammed on their brakes.
normally this would not be a problem, as my benelli has front and rear disc and stops VERY quickly. however i had been riding for quite a long time and my hands were quite frozen.
i already had my hand close to the front brake, but my hand was further from the rear brake. my reactions were slow, and did not engage the rear brake.
i locked up the front brake, slid, which i have NEVER done before. the arse end of the bike pushed around, and popped me right off the bike. i could have stayed on, but that meant hitting the car in front of me. i pointed a bit to the side and missed him, but did not manage to stay on the bike
owning a honda, and the lightest one around at that, i have heard this "the rear does only 20% or less of the braking, therefore is not very important. rear disc swaps are pointless, since drums brake just fine." arguement MILLIONS of times. drum brakes, properly set up with good shoes are adequate...
BUT a rear disc brake is NOT pointless or silly. rear disc brakes make a huge difference.
and may i ask where you got this 80% number? because thats the same thing i have heard about front wheel drive vehicles.... which are bikes are not. and there is also a very large amount of weight in the rear... ASK ME HOW I KNOW!