I think the ideal mod message would look something like this:
Hey it looks like your post, Board Deleted, was in the wrong section.
We'd like you to take a moment and familiarize yourself with the guidelines for each Board, then repost it in the correct one.
[Copy-pasta of Boards Guidelines here]
Move my post to:
[Dropdown Menu]
[Submit button]
One of the options in the dropdown menu would be "I read the guidelines, but I still think my post was in the right place." (not quite that wordy, though). If you choose that one, the mods will send you another message telling you which board is the right one and why.
Optional: if you choose the "I think it was in the right place" option, give OP a text box allowing them to explain why they think it was in the right place. Mods can read this, to help make their decision, and the Boards team can read this, to determine where the guidelines are unclear => make them better.
edit: made this into an OP