Are men really this easy to manipulate?

From the book Nudge, Page 3:

"... the power of small details comes from focusing the attention of users in a particular direction. A wonderful example of this principle comes from, of all places, the men's rooms at Schiphol Airport in Amsterdam. There the authorities have etched the image of a black housefly into each urinal. It seems that men usually do not pay much attention to where they aim, which can create a bit of a mess, but if they see a target, attention and therefore accuracy are much increased. According to the man who came up with the idea, it works wonders. 'It improves the aim,' says Aad Kieboom. 'If a man sees a fly, he aims at it.' Kieboom, an economist, directs Schiphol's building expansion. His staff conducted fly-in-urinal trials and found that etchings reduce spillage by 80 percent."