you see, the newer GTA's focus on restraining your character to one place at the start of the game, thats why they are on islands ! If you have swimming long distances, you have no restraint! It's like giving you a seaplane and a maverick at the beginning. But you should not die when you touch water, its not like hes one of those weird alien dudes (whats that movie called again when the alien melt when they touch sea water?). That guys idea of getting of respawning on the latest dock with a hurt on your health is the best idea yet, swimming would be bad, maybe, you cant really say its bad or good, thats up to the developers to decide. But I pray to god that the next GTA doesnt see you dying when you go knee high in water