You can get locked from Gmail if Google decides to suspend your Account. It has already happened to lots of users, even G Suite ones and good luck trying to get it back.
Google reallly sucks in this regard. You can also lose your account if someone hacks it and google cannot determine who it belongs to, so it belongs to no one despite not being suspended.
Examples on HN: https://news.ycombinator.com/item?id=22146082
https://news.ycombinator.com/item?id=22705122
https://news.ycombinator.com/item?id=4013799