Have you ever faced petrol pump cheating and how did you tackle it?

Three friends have reportedly been cheated at a petrol pump at Magadhi Road. Surprisingly their efforts to prove that landed them in jail. They were charged with vandalism. May be they did not tackle the problem in a right manner. I hope you always check 'zero' before the petrol tank of your vehicle is filled and the reading when it is completed? Have you ever felt that you have been cheated by the petrol pump? How did you detect it and what is the effective method of tackling such a problem?

KRS members may please narrate their experiences.