External leaks

The toilets on Boeing 777 aeroplanes come with a stern warning. "Flushing anything except toilet tissue down the toilet may cause external leaks and is a safety risk".

If this is true, then I assume what it really means is that the contents of the toilet, when flushed, are not stored on board but instead are sent rushing out of the plane in mid-air through some kind of Bernouilli tube. This would certainly explain the vicious suck which the toilet appears to have - presumably caused by the pressure difference between cabin and the freezing outside.

I imagine, therefore, frozen pellets of my pee raining out of the back of the plane at 300 miles per hour and landing in a trail like huge hailstones on the unsuspecting ground below.

The thought kept me entertained at 4am this morning anyway.