If I have to worry about whether or not someone will steal from me in my home, then they are not welcome here. It's basically the same boundary, only this time I'm no longer waiting for someone to rob me before I set it. I don't know when I'll be ready to have my sister back in my house, but right now I'm still worried so it's not time yet.
I trust that recovery looks like recovery the same way addiction looks like addiction. I think once I see some long term recovery it will be easier for trust to follow. I haven't seen that yet.