You all need to realise that now Andrea is dead Michonne is my favouraite living character, that doesn't mean I cant think she isn't realistic. I love her but she's just not realistic.
I agree with you. No one in their right mind would think about walkers hiding people's scent right away, and no one really could become that skilled in a little over a year with a sword. I believe they suggested that those two she had with her were her relatives, so maybe they all stuck together for a while before they turned. I remember in the first season Rick and the group smeared zombie blood on them to hide their scent. I wonder if they had decided to experiment, they would have realized the same thing Michonne did. I would love to learn more about her past.