When I am sitting inside eating lunch on tour and it starts to rain - I don't have to do anything. I don't have to carry rain covers or stuff all my gear in ziplock bags. My bags are waterproof to start with!
When my buddy dumped his bike on a dirt road decent [with my spare Ortliebs on it!!] the damage was limited to a couple scrapes...the bags remain waterproof.
Vik...is that fender flap made from a milk carton? Just curious as I need to come up with a larger flap on my front fender.