I’ve noticed the flies in Schiphol airport urinals the last few visits, but never knew their purpose. I admittedly didn’t put much effort into figuring it out now I know:
Fly into Amsterdam’s Schiphol Airport and, if you do what most people do after a long flight, you are probably headed to the lavatory. If you’re a guy, you’ll see that Schiphol’s bathrooms sports a feature many do not — urinals, with flies on them, as pictured right. Stare for a minute and you’ll notice that the fly doesn’t move. Look around, and you’ll note that the flies are everywhere — one per urinal, all the way down the row.
…It’s a target, plain and simple. Something for customers to aim at as they urinate.
This likely would not have been my first guess.