Ok cool but... Why not just not do that? Is the one month of revenue from people who forget to cancel, then cancel and are pissed about it, Worth it?
Since traffic from HN is essentially free I have no problem with an extended trial period :)
It's fair game in my book to use the tools Apple provides us as developers to monetize our apps. Other apps offering subscriptions do so in the same way... it's why Apple provides us the ability to even offer free trials.
I'm sorry you disagree, but this is common business practice.
edit: typo