First let me state that I am in no way suggesting that the trap in Phillip's photo should not be called...rules are rules after all. But, simply for the sake of discussion, what would be the actual safety hazard of that trap, if it was at an interior location as opposed to an unheated garage? I can see that a trap located where the standing water could be frozen would be a huge no-no, but I've never quite got my head around the issues involved in one like Phillip's. So, aside from the flex, can someone convince me why this particular trap poses a threat? Hi Richard, What comes to my mind is that it would be a place for critters to nest or if wet a place for scum to grow, either one causing a restriction. I'm sure you've seen ac condesate traps clog with scum. Then, when it dries it becomes like a plug. Just my thought...