Note that changing your payment details does not cancel your responsibility to make payments.
For post-paid subscriptions, e.g. AWS, you've already consumed the service and you are obligated (legally and ethically) to pay for it when the bill comes. You can't change your credit card details to get out of paying.
For pre-paid subscriptions, like a month-to-month SaaS application, I don't really see the issue with using burner accounts and cancelling them if the company makes it hard to cancel. From the company's perspective, don't they just cut off access when the payment doesn't go through? Its not conceptually much different from forgetting about a subscription until the card expires.
More to the point, if the company didn't implement dark patterns in an attempt to prevent users from cancelling, we wouldn't be here in the first place.
So this means I can say my name is Fake Customer and I live at 404 Main St, 95111 and it will validate just fine.
This is the same as if you purchased a prepaid visa gift card.