That's like saying run quickly now because I'm going to fire an RPG at you. The fact I told you to run quickly does not change the fact I fired an RPG at you.
A considerable reason in this is people are not meant to sit still for a long haul flight. DTV is a prime example of this. Your bladder too. While it is a good safety requirement to protect against the unknown external forces, it is not a defense against an accidence of their own cause.
Another way to think of it is I drive a wide load truck down the street with a at 5am every day. Some day I will be going down one street and hit something because the truck is too big. The fact I had lights flashing on top does not mean I am not responsible for the damage. If someone walked in front of the truck, then no as that would be a proactive contribution. I will have to anticipate this cost will occur sometime, that's why I get insurance from an insurance company (which for tax purposes is actually very similar to an investment fund). I could counter this by placing sensors all over the truck, and doing so may be able to lower my insurance costs.