Hi,
If you get locked out of your Block.io wallet due to too many 2FA attempts, you may experience some wait time while trying to reach their support staff*. The solution, I have found, is to reset your account's password.
If you cannot go through that process due to lost email or some other issue, this solution won't work, of course.
Just a self-help tip for anyone researching Block.io after having issues with their service

* Do they even have support staff?
Delayed support do really sucks on any services which this is one of the things I do seek when I decide to engage on a certain service/site because if I found out that they do have bad support then that's the time I do skip. The thing or self-tip that you said was just a common sense thing step for us to do. Don't bruteforce if you don't really know the passcode/2fa since you can just simply click the forgot password link.