It does have a checksum. That means error-correcting works just like in the article, by picking the nearest valid code. This could be built-in to the software.
It would take about 0.5 seconds of brute forcing for the library to figure out if you had gotten a word wrong, so that's actually reasonable.
Re:How I Stole a User's Siacoin
by logicallee on Friday June 16, 2017 @04:33PM
(#14572435)
Rather than a checksum, I think we're talking about something like a recovery record[1] or some kind of error correcting code, which is slightly different.
[1] like these - https://en.wikipedia.org/wiki/Comparison_of_archive_formats#...
While not the same, I'm reminded of the issue with etherium addresses where they've (after initially having no extra checking) started using mixed case to provide a checksum to detect incorrect entries. Otherwise, it's really easy to send coins to a very slightly different address due to a typo.
With Saicoin, it seems like just adding 1 more word could allow correction of mistakes like these. (And you'd end up with a round 30 words :).