This one comes from The Independent, from the daily Word column.
The writer of this "column" presented the following:

Whenever "In case" is followed by the word "of " it seems impossible to complete the sentence in a positive way.
He could not find it and put the case to the readers.
We could not find one positive ending either.
Yet there might be.

In case of...........?

When you take the word "of " off, you can go both in positive or negative directions.

I found it interesting so I put it here. Why does this word "of "
block a positive meaning in a phrase completed?