There's a much more detailed reason

Growing up in Gh, I often heard the short explanations why kids shouldn't do certain things.
In our hometown, you'd be told to hush if you started whistling after sunset. Why shouldn't you whistle? Well, go right ahead and whistle, and the dwarves in the forest will come running.
There were many more of these types of "reasons" to deter kids from doing lots of other things. They didnt make sense, but they served a purpose. Easier for hard-headed kids to remember.
The real reason was to prevent kids from disturbing serene nights with their whistling.

Here are a few more
- Dont sweep at night.
Cant remember what dramatic thing would happen, but it was to prevent people without enough light in their rooms, from sweeping away their valuables.
- Females don't braid their hair at night. Those that did, would never get husbands.
The real reason was that less light at night wouldn't help in getting the hair done nicely.
- When washing your hands at the faucet, don't allow anyone to wash theirs beneath yours. If they did, they would be spiriting all your wealth to themselves.
Real reason was to get kids to wait their turn and wash their hands with fresh water from the faucet.

Those old folks meant well. At the time, I guess they chose the dramatic effect to get their message across.

Do you have any similar ones to share?