I see it all the time with my app. It's stated several times on the sign up screen that it's auto-renewing. Yet, somehow, people are mad when the renewal happens, or the overdraft occurs, for a $0.99 purchase.
Doesn't matter if you don't read the paper that's delivered to your house every morning, the service is still provided. Same thing with app services.
If you signed up for it, you signed up for it. Not my fault if you fail to cancel it if you're not using/reading it.