I know how many apples are in a kilo. Without this knowledge I might not have a story.

Around the backside of the bus station in Vientiane, Laos, amid restaurants and knickknacks shops, a few vendors sell produce. I went is search of some fruit before taking the bus back to Thailand. It was a hot day and for the 12 hour bus trip home I thought I would splurge and treat myself to a few apples.

Seldom have I bought apples around these parts. I usually stick to the usual, bananas, papaya or pineapple, all of which are relatively cheap. Apples, however, are a bit pricy.

But a few weeks back I had bought some in Thailand. Six apples tipped the scale at one kilo. Sure, not all apples are the same size, but....

Near the bus station in Vientiane I visited one of the two apple vendors. A fat lady sat behind her wares, the scale right beside her. I picked out the apples. She put them in a plastic bag and weighed them.

Whoa! The needle jumped. Four apples equaled one kilo! And they weren't even especially large ones. And then, get this, she gave me a fifth one for free and the needle rocketed about 300 grams! Impossible! I thought. So I told her to re-weigh the fruit. This she did, with the same result. So I paid her the 10,000 kip (about $1.50) and went on my way.

But that scene gnawed at me. One kilo has about six apples, I told myself. And, how could the extra apple have weighed so much? I walked on back towards the bus station, puzzling over the situation.

Then I had an idea. Why not find another scale and re-weigh them? Easy enough to do, with all the vendors around. So I stopped by the second fruit vendor and borrowed her scale. The bag I had just bought, with five apples, that weighed about 1.4 kilos? It now weighed in at 0.7!

What to do? I have never forgotten to pack my self-righteousness when I travel, and I soon found myself marching back to the first vendor, knowing full well she had cheated me. When I approached her stand, I huffed and puffed and tossed my bag of apples down and demanded my money back.

And what do you think the vendor did?

Did she shoo me away like an pesky fly? Did her minions haul me away on a cycle rickshaw to begin the skinning process?

Far from it. Without saying a word, she calmly returned me my cash. And...

I looked at the amount in my hand. She had given me 20,000 kip. Twice what I had paid!

As I walked away I waited for her goons to come grab me by the collar. I turned the corner, but still no one came. I held the bills up to the sky to check for watermarks. Yep, they were genuine.

Now I had made a small profit, but I did not have any apples. So I went to the second fruit vendor and got myself a kilo.

But I was not content. The first episode continued gnawing at me. I have traveled the world and visited numerous markets. I have bought produce from Katmandu to Kyoto, from Cuernavaca to Cologne. Never, but never, had I suspected the scale to be off. I knew of the ol' put your thumb on the scale trick, and I often checked that the needle started on zero. But these spring-loaded mechanical devices far and wide had my fullest confidence. I was a sucker for the scale trope.

This shook my confidence. I could not understand why I had never thought that a scale might have been rigged. Like the first vendor's device, my self-image as a savvy Weltbummler was in need of adjustment.

So now, with my second kilo of apples in hand, it is easy for you to imagine what I did: I went straight for another scale. This kilo now weighed in at 0.9.

Of course, you are a step ahead of me. You are thinking, how did I know which scale was true? The answer, though not agreeable, is simple: I didn't.

But I wasn't going to let a small detail like that prevent me from stating my case a second time. I returned to this vendor, helped myself to an extra apple, thanked her and walked away. She mumbled something or other, but she wasn't itching for a fight.

I rode back to Thailand munching on my apples, wondering about the conflux of elements that contributed to this story: my knowledge of how many apples comprised a kilo; the fact that I had never questioned the integrity of a market scale; the fact that apples are the perfect produce for this story, because unlike eggplant or pineapple, this fruit is usually roughly the same size.

And, what to make of doubling my money with the first vendor?

This question seems to find a concensus with those I have spoken to. Hush money, pure and simple. If I entertained this thought at the time, I never thought of going to the cops.

Back home in Thailand, this experience haunted me. I shop often and buy a lot for my restaurant. Now I was really suspicious. So....

I know how to test these scales. A liter of water, by definition, weighs precisely one kilo. If I brought a liter to market with me, I could test each scale to see who was ripping me off and who was honest. But would vendors blacklist me if they knew what I was up to?

I was hesitant to do this. One Burmese fruit vendor had once refused to sell bananas to me because I was too finicky. Certainly if I scrambled over her produce and placed my water bottle on the scale that would be the end.

Nevertheless, with my water bottle in hand, I proceded to test the scales of the vendors I frequented. One by one, I mosied up and non-chalantly weighed my water. The veg lady, with whom we did bulk business, passed muster. The seafood vendor, a 20 something Burmese woman who I was most suspicious of, did too. And so did the other seven vendors. Not one, I am happy to report, had rigged her scale. And no one apparently was suspicious of my actions.

With some of my faith in humanity restored, the tom yam soup with the prawns from market tasted so much better.