I don’t think so—comments seem much more likely to end up with positive karma than with negative karma, except on some hot-button topics (politics, gender relations and seduction …). So getting enough karma shouldn’t be a problem unless you’re systematically talking about “unwanted” topics, or write particularly bad comments … in which case, them not being able to post top-level posts is a feature, not a bug.
I don’t think so—comments seem much more likely to end up with positive karma than with negative karma, except on some hot-button topics (politics, gender relations and seduction …). So getting enough karma shouldn’t be a problem unless you’re systematically talking about “unwanted” topics, or write particularly bad comments … in which case, them not being able to post top-level posts is a feature, not a bug.