This relates to People get lost and crash into meta - maybe we need roadblocks for their safety and the issue it's dealing with: people ask off-topic questions on here all the time. I think it's common knowledge that a non-negligible portion have certainly been question banned elsewhere.
In addition to setting up roadblocks, I think something else that would help is simply not sending people here so soon to begin with.
Let's consider the process a relatively new question-banned user goes through:
- Someone understands how their Stack operates extremely poorly and eventually gets question banned.
- The first thing they see is a message directing them to What can I do when getting "We are no longer accepting questions/answers from this account"?
- Once clicking that link they realise they're on, wow, a brand new Q&A site! An active one with lots of people! With a big ol' Ask Question button in the top right!
- They can't use that other Q&A site so hey, maybe they can ask their question here!
Since the user understands our Q&A network poorly enough they got question banned in the first place it's also very unlikely they'd recognise step 4 is a bad idea, or they want to do it anyway because they have nothing to lose.
My suggestion: What can I do when getting "We are no longer accepting questions/answers from this account"? should not be a meta post, but instead a page on the per-site help center users are directed to. This reduces the likelihood they'll wind up here, instead of the current approach which puts them on a downhill slope to wind up here almost immediately.
This won't stop all the off-topic questions we get but it may at least reduce the quantity and frequency.