We saw this all the time: my phone never got wet. Crack it open with the ol’ spudger, find a blue-green mess.
Had one lady bring hers in smelly like pee: her cat.
Had another pull it out of her cleavage: full of salty crystals and moisture.
I never went off that stupid paper, since the moisture of the PacNW air during rainy season is enough to set them off.
But yeah people treat their expensive, sensitive gadgets like shit
But that experience leads me to believe those water indicators are considerably more sensitive than the electronics themselves. If I had gone in there complaining about some weird issue instead of simply wanting a new battery, would the lack of apparent corrosion on the board still lead that Apple employee to conclude that the board wasn't water damaged?