[hulitu]

> reduce the effectiveness of waterproofing

If your phone has a hole (usually the charging port), the water will get in.

[Dilettante_]

That's like saying you get water into your brain through your earholes when diving

[viraptor]

That's just wrong. A port is not necessarily a hole through the case. It may be just a concave area. The water doesn't necessarily get in through ports either - there's lots of water-tight designs there.