Splash really should be a problem, and in the first season they did at least try, once, to avoid getting gunk in their eyes. Unfortunately, a major unspoken Hollywood rule precludes main cast actors from covering their hair unless it's a character thing.
Anyone remember the first seasons of Stargate SG-1, Flashpoint, etc.? They all had helmets as part of their kit. Then, they started consistently walked into firefights and other dangerous situations without them... Why? To make sure their hair still showed.