I'm reading the wikipidia page on Panmixia.
Panmixia (or panmixis) means random mating. A panmictic population is one where all individuals are potential partners. This assumes that there are no mating restrictions, neither genetic nor behavioural, upon the population and that therefore all recombination is possible. The Wahlund effect assumes that the overall population is panmictic.
In genetics, random mating involves the mating of individuals regardless of any physical, genetic or social preference. In other words, the mating between two organisms is not influenced by any environmental, hereditary or social interaction. Hence, potential mates have an equal chance of being selected. Random mating is a factor assumed in the Hardy–Weinberg principle and is distinct from lack of natural selection: in viability selection for instance, selection occurs before mating.
Now, I would guess from this definition that Panmixia is a condition that almost never occurs, that in the vast majority of cases, there is some sexual selection going on which makes some pairings more likely than others.
But the way the page is written seems to suggest that this is a pretty normal condition of populations, or at lead doesn't mention that it is a "spherical cow" abstraction.
Am I missing something here?