Just Google "health insurance recision congressional testimony". There were many, many hours of testimony about the dishonest practice.

It was systemic in the industry before it was banned by the ACA/Obamacare. This is one of the most important features of the ACA.

I've posted below only one of the first appearing links to articles on the testimony of industry insiders [1]. I don't have handy the link to the video I found most memorable. It was a woman who worked at a large insurer, who rescinded the insurance of a man with an expensive disease, who'd never missed a payment, and who died fighting to get the insurer to pay. so he could get treatment. She felt badly enough about it to testify, and was also promoted for saving the company money.

Just because it sounds outrageous and dishonest does not mean that people won't do it.

[1] https://abcnews.go.com/Business/Health/story?id=7911195&page...