Robin asked, in relation to correlations between sexual prompts and apparently innocent behaviors:
So what would happen if we all became conscious of the above behaviors being strong clues that men are in fact actively trying for promiscuous short term sex? Would such behaviors reduce, would long term relations become less exclusive, or what? Maybe we just couldn’t admit that these are strong clues?
It isn’t usually activeness that people mind most in others’ wrongdoings, but conscious intention. These usually coincide, but when they don’t we are much more forgiving of unintentional actions, however active. So if it became known that an interest in cars or charity was a symptom of sexual desire I think it would be seen as similar to those other ‘actions’ that show sexual desire; a bad message to your spouse about your feelings, but far from a conscious attempt to be unfaithful.
While it’s not a crime to have physical signs of arousal about the wrong person, I assume it’s considered more condemnable to purposely show them off to said person. I think the same would go for the changes in interests above; if everyone knew that those behaviours were considered signs of sexual intent, realising you had them and purposely allowing potential lovers to see them would be seen as active unfaithfulness, so you would be expected to curb or hide them. Most people would want to hide them anyway, because showing them would no longer send the desired signal. Other activities are presumably popular for those interested in sex exactly because conspicuously wanting sex doesn’t get sex so well. If certain interests became a known signal for wanting sex they would be no more appealing than wearing a sign that says ‘I want sex’. This would be a shame for all those who are interested in charity and consumerism less contingently.
Meteuphoric 
Really, I don’t understand how anyone could be surprised to learn that men spend money on visible status signals chiefly to obtain promiscuous short term sex. How is this news?
“If certain interests became a known signal for wanting sex they would be no more appealing than wearing a sign that says ‘I want sex’.”
But that is not primarily what they are. Primarily, they make the person more attractive and therefore more liable to get sex. This is evidence that the person wants sex, but conveying his own desire is not the primary goal of the activity; the primary goal is to elicit desire in another. Similarly, eating lunch is evidence that one is hungry, but the primary purpose of eating lunch is not to tell people you are hungry; it is to feed yourself. And it works whether or not it is known to be intentional. Similarly, putting on makeup makes a woman attractive whether or not we are aware of its purpose. It is no secret that women put on makeup in order to be attractive. But it makes them attractive all the same.
A better parallel might be high heels and make-up. Fashions and adornments are considerably more conspicuous and voluntary than the state of one’s nipples. Nevertheless there are norms that dictate the acceptable range of behaviours that serve as mating dances and sexual semaphores. Status can be lost for sending out sexual signals that violate the (often tacit) rules that a culture prescribes for a given time, place, and social position.
Although conspicuous consumption isn’t usually considered a sign of imminent extra-pair mating, we do sometimes show disapproval of habits of consumption that are considered inappropriate for people of a certain age and social position. A middle-aged man who suddenly takes an interest in sports cars and body building is sometimes said to be undergoing a midlife crisis. Nouveau riche are considered gauche if they leave extravagant tips or purchase flashy consumer items.
Thorstein Veblen wrote about these ‘canons of pecuniary repute’ in his Theory of the Leisure Class. Being able to follow mercurial and arbitrary rules demonstrates social acuity. It also demonstrates that one has surplus time and energy to devote to non-vital pursuits (Cf. Veblen’s rules of conspicuous waste with Zahavi’s handicap priciple).