Could be cumbersome to do that, discouraging not really committed voters. Or maybe we want to discourage less motivated voters?

To me, sensible approach to voting should be a common sense by moderator.
Obvious spelling mistake should be handled automatically: “Fillippone” “Filippone” or “fillipone” have little doubt about voter intention.
“Lafu01” vs “Lafu” should be handled with a little bit more care, maybe tagging the original voter.