those scales were wrong. but before you start thinking the airlines are out to get you, it's actually the airports who are responsible for servicing and monitoring the scales. so what can you do if you think a scale is off and you're being unfairly charged? first check it while empty. if a scale doesn't read zero ask a ticket agent to hit the reset button. >> we want it to be fair for both the airline and the customer. >> reporter: don't be afraid to move your bags around. sometimes a slight shift can change the weight that the scale displays. >> so this says 101 pounds even though you have 100 pounds of weight on it. >> right. that's why we do the shift test. >> reporter: finally, if that weight seems really close to the limit, try another scale. becky worley, abc news, los geles. >> keep shifting till you get the weight you want. >> that's what you do when you're weighing yourself on a scale, right? >> one foot on, one foot off. >> move one foot, right? >> new york where the airports were the biggest offenders. >> some of them were surprisingly accurate like in atlanta. >> absolutely.