* They forget, and then retain a monthly subscription charge. * They end up watching some small thing casually and it just remains forever.
The first point, especially, is a big part in why subscriptions work, I believe. Hell, it's definitely why Crunch Fitness is still in business (because they make it impossibly hard to cancel).
This is totally anecdotal, but I'm curious how many people actually set out to sign up, binge, and then immediately cancel.
Also - an aside. I'm pretty fed up w/ services that charge a monthly subscription, and make it totally unclear what happens when you cancel. Some completely shut you off immediately (which is just about the scummiest thing ever, since you... paid for the month already). Others let you finish out your month. This is super anti-consumer IMHO.