The book analysed extensively the level of corruption in Sumo-wrestling, a high profile Japanese sport. So why not a high profile Australian sport. I shall resist naming names, but there are times when I am suspicious given the incentives.
1) Selection trials often get in the way of "tapering" the training regime. ie, faster times would be more likely at big meets, if one could avoid having to swim hard to qualify, rather than sticking to a training regime.
2) This is more of a problem in longer races eg. 550m or 1320 meter races, for instance, and not so much for the 90m and 180m type distances.
3) The general public doesn't really know the qualifying rules, while top swimmers would know if there was a way to get into an event without swimming in the qualifying final.
4) A casual, pre-race gentleman's agreement between swimmers is unlikely if they are coached by different coaches.
5) In certain races, it is very easy to predict the places each swimmer will get, in advance, if there is considerable difference between them.
6) It is quite easy to fake a false start.
7) If you are going to false start, better it be in the first heat, rather than the final, so that you didn't waste that energy qualifying for the final for nothing.
8) How does a swimmer get a jaw injury that requires surgery, and how come his mouth can open so wide afterwards.