Yes. If that happens, you shouldn't give that website your business.

Won't I only know that after it happened?

What if they deem me abusive after several months of using the website?

This is actually pretty common. Won’t be long before we see another HN post about someone getting banned from a platform with no idea why and no recourse forward.

Actually similar happened to me recently. I woke up to find my PayPal account close and no one can tell me why.