According to Apple: "A triggered indicator will turn red or pink, as shown in the examples below, indicating that the module(s) to which the indicator is attached has been exposed to liquid." So, yes, you said PINK shouldn't nullify the warranty, but then you went on to say how humidity "might" affect the electronics and they'd be withing their rights to nullify the warranty. Apple states humidity will not affect the sensors. As Abiyng87 states, Apple needs to upfront with their customers. Since, the OP's tests seem to show humidity affects the sensors they need to change the policy or tell us that we better get cases that are water resistant if we live in Houston or DC. What Apple needs to also do is show us how these sensors are not going to be affected by humidity IMO. They can refute the OP's tests, since for all we know they are bogus. Anyway, from what we know at this point, PINK nullifies the warranty and PINK is caused by humidity and Apple states humidity will not cause the sensors to activate.