You need to try very very hard to get a permanent ban on Stack Overflow. And even most "permanent" bans are only for 10 years. There are some exceptions, but it

You need to try very very hard to get a permanent ban on Stack Overflow. And even most "permanent" bans are only for 10 years. There are some exceptions, but it's rare and only after persistent serious long-term abuse and all the shorter bans didn't work.