How likely is to have your account actually banned?

I know everyone says "Don't connect this, don't use that" But how far does that go? Do I have to open a game? Just open Nintendo store? I've been using the normal side to look at games at the store because I wanted to play dead by daylight, and (this is a second hand switch) the last owner has a lot of hours in Pokemon online (the champions one) on the original system, even though it's a jail broken