It does work. People are distracted and are not reading every message correctly. And payment processing in the appstores is also kind of easy - so you might be able to scam a few people into subscribing and they might not notice this directly. You know that you are not checking your credit card bills in details every month. So you can get a nice revenue stream of unsuspecting customers for a few month until you’ve burned down every little bit of trust and user base you had