I think if I am not mistakenly I have came across such discussion here in the forum, although I don't know how it was handled but I could remember someone say of self-exclusion and yet the account was still active and was continued to gamble on the account.
What mostly happened is that to me, I feels like the casino would have to give time or duration for automatic deactivation of that account, maybe they don't know if such user mistakenly click on self-exclusion without know the meaning of that and if such happened they could request for reactivation they still have little grace to have back their account. That is what I felt some casino doesn't go immediate effects to deactivate accounts.