Q. I recently took a trip where I was dangerously close to being overweight with both my checked bags. With this in mind, I weighed both my bags with a certified scale before leaving the house and found that each bag weighed under 40 pounds. When I got the check-in counter, however, my first bag weighed in at 57 pounds on the airline scales, the other at 42. Obviously, I switched some things around to make keep both bags under the 50-pound limit. Is it possible the airlines' scales aren't zeroed automatically? Or is this a conspiracy to add up those "overweight" charges?

A. I doubt it’s a conspiracy, but you should never trust airport check-in desk luggage scales. Most local jurisdictions have a bureau of weights and measures responsible for checking the scales at least annually, but a lot can happen between checks. It’s a good idea to carry a portable digital luggage scale if you typically travel with checked bags weighing near the 50-pound “overweight” limit so that you can check the accuracy of the airport scales. They’re available at local luggage stores or online.