I agree. The high school kids up the road use the bass boost and gain knobs as volume controls all day long and we used to sell a package deal with the US Amps XT1600.1 running two L5's. Even with all their "stupid" abuse, I NEVER had one returned for warranty. I would have to figure sub was just worn out or something. Maybe even amp to speaker wiring shorted somewhere along the lines?
Again, I know people here have their feelings on Kickers, but part of the reason we carried them so much is that we never had to deal with warranty issues on them. Very low defect rate for a mass produced sub in this price range.