My passport has been through an entire wash cycle. Many dozens of immigration officers have never said a word. I have however gotten several stern lectures from assorted rent-a-cops. Including the TSA, but then again the TSA disallowed my US passport as valid ID even before it was washed. (Actually, the TSA/rent-a-cops picking at the laminate has caused more damage than the water. I tend to watch them carefully now and only show when no other ID will suffice)