Public sink use???

People who have followed my comments on other threads know that I am keen on having sink cubicles in facilities blocks (as provided by the CC but not by lots of commercial sites!). On trips to CC sites this summer I have been puzzled to find people using the public sinks (provided for washing hands after using the urinals and water closets) for strip down washes and shaving - when all around were empty sink cubicles (obvious to see as the doors were open!). What on earth is the point of not using the sink cubicles?