I'm thinking something similar to Women's Badminton at the 2012 Olympics. There, some pairs actively attempted to lose their games to gain a more favorable draw in the next round.
Has anything like this happened in chess? I'm aware of the Candidates tournaments of the past where Soviet players allegedly played quick draws against each other to conserve energy against Fischer, but I'm not aware of intentional losing.
As an example of what would qualify, suppose in some 20-player tournament, the top 6 qualify for the next stage (this has happened in Candidates tournaments in the past). In the penultimate round, the runaway leader Alice has more or less qualified, but the 6th and final qualification slot is still up for grabs, with three players Bob, Charlie and Denise in contention. Alice is scheduled to play Bob in the round. She thinks Denise is the most threatening opponent, so it's in her best interests to lose to Bob and give Bob some help in qualification.
I'm not interested in match fixing to, e.g., make money in the betting markets; I'm only interested in losing for personal gain because of the crosstable & tournament format. I'm also not interested in draws - only intentional losses.