When we broke the news that AT&T is pushing updates to older Android devices to finally enable sideloading, and with the Infuse 4G being its first phone to sideload out of the box, we naturally assumed AT&T will continue to leave its future phones open. And that assumption has been confirmed, as Ma Bell went straight to the developers to inform them of her intent to no longer lock out sideloading on future phones.
Again, props to AT&T for finally changing its stance, even if it took the Amazon Appstore not working to make it happen. No matter how you slice it, it's a win for the customer.
Thanks to everyone who sent this in!