Ok, but I've never heard the phrase used that way.

That's not what swings and roundabouts means though. Like, not even remotely. It's also not what I said.

Totally IMO.

Like whopsie not a biggie (for both stories, ironically ofc).

It's similar to "what goes around, comes around", since swings and roundabouts go back to the same place.

As in: If you mock someone one day, they might mock you back another day.

In https://interestingliterature.com/2015/09/the-interesting-origins-of-the-phrase-swings-and-roundabouts/

But he’s also sometimes credited with popularising, or even inventing, the phrase ‘swings and roundabouts’, meaning ‘a situation in which different actions or options result in no eventual gain or loss.’ In other words, ‘it’s all much of a muchness’. Chalmers used this phrase – and the accompanying sentiment or meaning – in a poem titled ‘Roundabouts and Swings’, which was first published in Chalmers’ volume Green Days and Blue Days in 1912. The original poem is interesting not least because it cleverly employs existing expressions (round and round, up and down) to describe the pattern of financial profit and loss experienced by the travelling man. In doing so, and in using the symbols of the roundabouts and the swings to reinforce this sense of gain and loss, the poem arguably helped to bring the phrase to a wider audience

And that is several square millimeters of cerebral cortex that you no longer have available for other patterns.