Defaulting on their credit card bill. Or the account ends up having been started by an identity fraudster. Which also ends in default.

That seems backward. The people I’ve known that spend a lot of money on adult entertainment are exactly the group that pays their bills.

This. I dont know who do you need to be in order to pay for the porn that you can pirate for free. In case of games or music or movies there is collecting and convinience, but porn is pretty much opposite.

But at the same time chance of "oops it's not mine" charbacks likely much higher compared to other spending.

Then why would they want to stop getting these red flags?