I was with you until the past part. We don't know anything about Michoone or what she's been through to make her so jaded about new people. One thing that shows up in the series more often than not is that nothing is as it seems. She wants her sword back so she can defend herself if she has to. They are in the middle of a zombie apocalypse. Any moment can be your last.
Additionally, why does she have to trust that these people don't have alterior motives for taking them in? In a world where resources are low what does she owe them now that they, what's seems like forcefully, took them into their camp and had them locked in a room with 4 guards. Andrea hasn't seen the worst part in people so she is green as a leaf. But Michonnes isn't so easy fooled as her guard is always up for reasons we don't know; from her personal experience.
I mean we see what the governor is capable of as audience members. Why would we say Michonnes is being unreasonable in her skepticism when in fact we know things aren't as they seem? I wouldn't be surprised if Andrea and Michonne are trapped and won't be allowed to leave. The governor is obviously milking them for information on other camps, specifically Ricks, not that they know anything about ricks camp. So surely the governor can't allow them to leave and squeal on their location right?
I'm on team skeptisim from the start. You can't trust anybody new. The show has stressed this from day one.
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