> automatically kicking a user off would also probably be bad.
No. "Sorry, subscription has expired, please re-up your account" is an extremely reasonable UX.
The whole "free period but we'll auto bill you after" is a shitty dark pattern that mostly exists to extract value from life admin errors. The people who got enough value to justify the cost would've paid anyway.
Exactly, this is one step from selling older people overpriced pots and rugs.
Or you can just add a reminder before the free period expires
Or they could just not autocharge people, or allow people to decide whether to autorenew or not when they sign up. The fact that they don't do that shows that they're trying to pull one over on people.
You can do that, but that's a dark pattern.