The fact that Herschel was bitten and is still not a walker proves that the theory of the "active virus" mentioned in the answer you linked to is not quite right. If it was, his body would have been infected far quicker by the introduction of the walker saliva/fluids directly into his bloodstream than Michonne getting covered in some entrails.
It's been at least a few days since Herschel was bit. As of the end of S03E06, it's been at most a day since Michonne came into contact with infected blood.
So far, we have not seen any instance of survivors being infected just by coming into contact with infected blood. They have only turned after death.
In fact, in this interview, creator Robert Kirkman confirms that contact with blood is not enough to turn a person. (emphasis mine):
This is a real Comic Book Guy question — but do I gather that if someone swallows a tiny bit of zombie blood they won’t turn into one of the undead? There was a lot of it being sprayed around this episode.
Yeah, people to a certain extent think of zombie blood as being like the blood from Alien. You know, in the Alien movies it’s like, “Oh god, if it touches you, you explode!” or whatever. Whatever it is that turns these people into zombies is in them already. So the idea of getting zombie blood on your face, which happens all the time, and it turning you into a zombie is something that’s just not the case.
Now, that doesn’t make the zombie bite any less lethal. You know, breaking the skin, having that kind of contact with the toxicity that zombie mouths would have, would be something that causes an infection that definitely would lead to your death and then the thing that’s already in you would turn you into a zombie. So there is a science to this, to a certain extent.