The fact is the person was double-clicking a file in a list to view its contents and Excel was trampling it. Nobody in their right mind will waste time to open Excel first, use import feature, re-navigate to the file they were already looking at, and go through the import dialog just to see what's inside.
Trampling it to me implies that Excel was somehow modifying the contents of the file. Which it doesn't do by double clicking on the file and just viewing it. Do you mean that the data shown in Excel wasn't what was expected because of the auto data conversion?
Believe me, I was blown away just the same. And it's not like the accountant clicked a save button of a on-close dialog, no. Opening a CSV file was enough.
The fact is the person was double-clicking a file in a list to view its contents and Excel was trampling it. Nobody in their right mind will waste time to open Excel first, use import feature, re-navigate to the file they were already looking at, and go through the import dialog just to see what's inside.