It's hard to believe customers are happy with it. I find it shady if you were to try all the cards I added to the product without my permission.

I'm okay with you sending me an email before you try, as long as explicit consent is given. However, if I don't care to change my primary card after the first attempt, that means I don't really care about continuing the subscription.

Happy to be wrong if you prove it with the data, though.