Attending Mindfully Versus Without Mindfulness

In this answer by ven. Yuttadhammo, it is said that depending on the level of concentration and mindfulness of a person, attending to certain states can result in either wakefulness or tiredness. Hence, I wonder: Is it the case that strong mindfulness tends to counter unwholesome states merely by observation, and that without mindfulness these states persevere and may worsen? E.g. a person meditating on a bus mindfully will decrease hindrances, whereas a person mindwandering might increase them? If so, then I ask: Does this entail that strong meditative states 'burn' unwholesome states because of a mindfulness absent from daily life?