OK I have to ask. How does a no-seeum from the sand reach someone's back?
These insects use
decaying vegetable matter as a food/water source.
..........................
When you sit on a wooden deck that has dead leaves or dirt in the spaces...
When you sit on sand, even though you can't "see" leaves and moist decaying things...
When you touch, lean against, or sit on that rope that serves as decor...
When you walk along an intertidal wash zone looking for shells...
When you sit on a stump...
When you lean against parts of a moist wooden building, like a gear locker area...
When you ride in a boat that has exposed wood and uses cotton lines...
When you walk into any building with a simple plank floor over sand...
You might be a [-]redneck[/-] sand fly meal.
Any dockside bathroom facility is just as prime a feeding ground as a gear storage area. It's moist, not much moving air, wood (wolmanized or not) is decaying and becoming prime real estate for no-see-ums.