The reality is Apple cannot legally advertise and sell an iPhone with an IP rating (held to an internationally defined legal standard) and deny a warranty claim that falls within the scope of the advertised IP rating. What they state in the disclaimer is irrelevant.
Water damage was previously not covered because they didn't advertise and sell the iPhone with a defined IP rating.
I'm not sure you're a lawyer. I know that I'm not...
"Resistant" is an interesting wiggle-word, regardless. I remember when watch makers started moving from the term "waterproof" to water resistant." Personally, I've always taken that to mean, "If it gets wet, I have a high probability of being lucky." It was done to make clear that there was no promise being made. "Resisting" water at depths up to 1 meter does not necessarily mean it will succeed.
As they Borg will say (at some point in the Star Trek future), "Resistance is futile!"
When we're talking about manufacturing standards like IP ratings, it's generally based on a certain (high) percentage of new product samples meeting the specification, or 100% of a limited number of samples meeting the standard. It usually means the product passed the test at time of manufacture. It's less likely that the testing process requires simulated aging ("passes the test at a simulated age of 1 year," let's say).
It comes down in part to this; seals can and do fail due to manufacturing defect, age, temperature (ask NASA), normal wear-and-tear, and abnormal use (abuse). If the phone is operational, then they could get a hardware diagnostic that reports the state of liquid contact indicators, barometers, etc., but it still doesn't tell them how/why the liquids got there, and "how/why" is the bone of contention.
Determining the actual cause may require laboratory testing, and that's not something easily done when someone walks into an Apple Store in immediate need of a replacement. The staff will inspect for signs of abnormal use/wear-and-tear. They'll listen to the customer's description of what happened. They'll then make an educated judgement call.
Apple is making several bets:
* Enhanced water resistance will pay off for Apple in fewer accidental damage claims under AppleCare.
* Enhanced water resistance will result in more happy customers (fewer heartbreaking accidents), resulting in more repeat business.
* Enhanced water resistance will result in greater consumer confidence that buying an iPhone for a 10-year-old carries less risk than previously (more sales).
If building to IP67 results in fewer damaged units (and by the way, the "6" refers to dust particle intrusion), it means there will be
fewer people showing up at the store, whether they claim warranty coverage, or not.
Sure, some people will treat their iPhones with less care, because they believe they can withstand greater abuse. However, most people will continue to be careful - they're already conditioned to do that. While some people think, "I can do this because I'm covered if something bad happens," there's also a (probably large) population that doesn't want something bad to happen at all. The inconvenience of loss-of-use and obtaining repairs is something to be avoided.The knowledge that the phone is water-resistant will not change their behavior.