Income tax - down the toilet

This item is of a personal interest to me:

The Suddeutsche Zeitung newspaper said authorities recommended the 1.5 million truck drivers in the country keep records of how often they go to the restroom and how long they spend on the toilet, so they can accurately determine how much of their income should be written off when their taxes are calculated...

I am not sure I understand how sitting on the toilet allows one to write off one's income, but if I find a similar regulation in the local tax code... yeeehaw! - our income tax authority will be deep in er... debt, I can assure you.