There still is one way I can get wet though, walking through long grass or ferns in the morning after a heavy dew or heavy rain. Even with a rain skirt on my knees can get wet, the drag of the grass and ferns can begin to open my skirt but I've solved this by re-using an old cheap pair of waterproof short running gaiters, they cost me about £10 at the time. I've had them for years but have never used them, until this year. I just wrap them around my knees and snap them together, 5 seconds on, 5 seconds off, the bottom edge over my gaiters, the top edge a few inches above my knees. Dry knees every time!
I can even picture two places where I suffered wet knees in the past, walking through long grass between Alston to Garrigill and walking through very wet ferns at the end of Lake Coniston after an overnight and sustained downpour.