I don't think it's necessary or sensible to show the confirmation "live" before unlocking - it does show "Your user name was not found" when you try to unlock with a non-existing user name.
In any case, the latter option is definitely safer, because there's always a possibility someone has found out user's LFS password for the site, but doesn't know how to access their email. In case the current unlock code becomes obsolete instantly when someone requests a new one, one can simply annoy other users by requesting new unlock codes and preventing them accessing LFS with their older unlock code.