You can "vouch" for them, which makes them non-dead (and upvotable again). But, yes, it does have some karma limit - I'm not sure if the specifics are documente

You can "vouch" for them, which makes them non-dead (and upvotable again). But, yes, it does have some karma limit - I'm not sure if the specifics are documented anywhere, the FAQ just says "small karma threshold".