Never said it was the last word.💟 but yea good point
The last word is a checksum. When you restore your 11 words the 12th word can only be a few options.
Discussion
I like the idea. I think a better approach would be to stamp your 12 words then keep the passphrase in your head. Or store it separately creating a quasi multi sig.
This would require you to make a new wallet, and move your funds (more risk), but the good news is you can use the same 12 words from your stamped wallet and you get practice creating, restoring sending, receiving.