Named for the trap it is: easy to check in, impossible to check out. Subscribing is a single joyful tap. Leaving is a corridor — a retention screen, a “chat with us,” a phone line open weekdays only, a cancel link three menus deep in grey 11px text.
None of it is an accident and none of it is hard to fix. The rule is 30 years old: give people a clearly marked emergency exit. The design word for the fix is symmetry — the way out is as wide as the way in. Anything more asymmetric than that isn’t a UX problem, it’s a business decision wearing a UX costume.
The tell you’re in one: the effort to leave is wildly out of proportion to the effort it took to arrive. Feel exactly how the trap works on you in the linked round — then you’ll spot it in the wild every time.