We all know ONA bags. Awesome, incredible, beautiful, I have the Prince and Bowery in antique cognac and I love them. The craftsmanship is amazing and the leather is beautiful.
But water doesn’t love them. Leather and water is always a bad combination, like mixing medicine and heavy machinery, or alcohol and skydiving. If you want to destroy a leather bag quickly, take it out into the rain. I have no doubt your equipment will survive, the leather is thick and it will take a while for the water to penetrate, but that’s only part of the problem. When you are paying the sort of money you are for ONA bags, I expect the bag to survive unscathed as well.