As another comment notes, they've probably had the code to do this for a while. Why should Rogue Amoeba continue to sit on it instead of taking the chance? Unless they were banned from the App Store entirely (unlikely based on past practice and probably less of a concern since their app was a free add-on anyway), they'd have lost nothing (and gotten a decent amount of sympathetic publicity in the process).
Hey everyone can do whatever they want. I'm pointing out the reality of the situation is not one of ethics or legality (see grandfather). The reality is if you play close to the lines, don't be surprised if you're found to occasionally be out of bounds.
As another comment notes, they've probably had the code to do this for a while. Why should Rogue Amoeba continue to sit on it instead of taking the chance? Unless they were banned from the App Store entirely (unlikely based on past practice and probably less of a concern since their app was a free add-on anyway), they'd have lost nothing (and gotten a decent amount of sympathetic publicity in the process).