You skimmed when you should have read.
A few years back, I participated in an event ride, and I rode my beloved Paramount, aka the zippy fast bike. 15 miles into a 65 mile ride, a torrential ride dumped an amazing quantity of rain in 20 minutes. There was indeed a rooster tail of water, and while I did have a saddlebag, my saddle did get really wet too. I have always used proof hide on the top and bottom of the saddle. By the end of the ride, I could hardly believe the damage done to my saddle. Once the saddle dried out naturally, a week later I might add, I was able to retention the saddle and take up most of the stretch. There are few disturbing looking stretch marks, that have not done any lasting damage. If the saddle ever gets wet like his again though, it will be a lost cause.
The amount of moisture coming off of my backside spread over the area of my backside is trivial.