Pre paid auto ERNAKULAM north railway station Over charging of Drivers

Y do we prefer pre paid auto? We believe that they won’t cheat us. Today I came from North Railway Station to Vazhakala. The price was Rs104 and the driver was screaming at me for Rs 130 and bcz of him the road got blocked. Is this the thing we expect from Prepare auto. Then what’s the difference between this service and usual auto.