Depends where in world you are.
Minium legal penalties/regulations for over booking and failing to get extra passengers to destinations in the US on time, virtually non existant.
In EU, for example, far less common due to legal penalties.
By raising the minimum penalty other countrys have made the numbers not ‘add up’ for airlines that want to play the over booking game.
In short, frequent over booking is mainly a US thing. In my life probably took over 500 flights around the world, only ever seen over over booking issues in the US.
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