I have a big blue suitcase I like to take on trips. It can hold a lot of stuff. Too much stuff, actually.
Several times I have had to unload things from this suitcase into a carry-on or other bag to keep it below the 50lb weight limit. This has happened so often that this morning, I got the bag packed and then put it on the scale.
The bag topped out at 54 lbs. So, I started moving things around and after some serious rearranging managed to get the scale to read 49 lbs. I weighed three times, just to make sure.
However, I told the girls that I needed to weigh my suitcase first, just in case the airport scales didn't agree with ours from home. Sure enough, my suitcase weighed 52 lbs, and I started looking for things that I could remove.
There weren't many small, heavy things left, so I started to get worried.
Then, in one of the outside pockets, I found a large bag of rocks.
It seems that one of my children (who shall remain nameless because she is self conscious about this story) had decided to bring some of our larger fossils to show her cousins and had put it into my suitcase "by mistake."
We corrected this "mistake" right away, and my suitcase dropped down to 48 lbs. I still got an orange "HEAVY" warning tag stuck to my bag, but there was no extra charge.