The QuickBooks checkout flow incorporates a highly dubious bait-and-switch tactic regarding data privacy.

The "Save my card" option appears disabled/grayed out by default.
The user is forced to provide a phone number to continue.
Upon entering the phone number, the "Save my card" toggle is automatically triggered to the "On" position.
This design relies on the user not noticing the state change after they’ve already "confirmed" the button was off. This is a textbook example of trickery designed to harvest credit card data under the guise of a required field. It is sly, anti-consumer, and should be addressed.