hmmm, maybe this is just me, but I don't think that she doesn't trust you. If she didn't, she would have stopped her car right away to find out where her child was when she didn't see her from the view from the road. I think it's completely normal for a parent to question where the child was if she couldn't see her. Also, if my child had a boo boo on his hand I would ask as well, whether the rovider knew what happened or not.
I know what you mean about feeling under the microscope. It's an uneasy feeling. A few months ago one of my dcb's started telling his Mom that he is in time out all day and that I tell him that hes bad and that I hate him. NONE of which are true and he always had great days. Mom questioned me, and I felt terrible at what they might be thinking. I felt like terminating just because of the awful uncomfortable feeling that came with that revelation at what dcb was saying. But they didn't pull him from care because they trusted me....did she give you a vibe like she was really upset? Like she might want to pull your dcg? I feel like these might just be normal questions to ask but it left you feeling uncomfortable. Maybe?