Here is an example with ~10% returns, although of course no information what specific pattern (e.g. maybe a lot towards the end, or something like "bought 8 expensive things to compare with the intend of returning 7"). https://www.theguardian.com/money/2016/mar/18/banned-by-amaz...

What's IMHO worse is that they remove Kindle access etc as well (I think here in Germany they've been sucessfully sued for that, so not sure if they still do it)

Yes. I also use Amazon Cloud Drive for my external backups. So if they ban me from the store, they would also ban me from accessing my backups.

10% is a lot though and another one in the article is ~25%. Typically it should be more like <1%. I am not sure it's a great policy but it's their store. It's also only one side of the story as well so who knows what amazon's side is.