In my case i had my cellphone in my pocket in my pocket while working out. This is BS in my opinion because water never actually touched my cellphone. Further, I was denied a warranty claim on my (UN-used) phone headphones (which had a broken microphone), because of this sticker. How does this sticker have anything to do with the headphones - that I NEVER used??
All that i suggest here is to put a drop of bleach on the indicator and it will turn from red back to good 'ole white. check out the pics!
Step 6: Aditional time
A quick note: on iphones there is one of these indicators either on the headphone jack or under the bottom iphone cable plug. Same trick should work for iphone. I would post pics but i need my iphone to take the photos :)
good luck !!!!