I spend a lot of time around water, so I have my iPhone in a Lifeproof case. You should've seen the look on my friend's face the other night when we were sitting in his jacuzzi and I turned my phone on and purposely submerged it two feet under water!This is why we should ALL have a cheap battery to use around water. Although, I have known multiple people that have jumped into pools with cell phones in their pockets. A couple of them were iPhones.
As far as mods, that's one reason I bought a Reo. Fully mechanical, no electronic parts. No big deal if you take it swimming - rinse it out, dry it off, put in a fresh battery and get back to vaping. In fact, if you look at the Reosmods website, his maintenance video shows him cleaning the Reo by washing it in the kitchen sink!