M.D.
I would ask - because I keep open communication with my kids teachers. I wouldn't care what was going on with the teacher, like you said, but I would want to know how to get a hold of who was with my child that much of the time.
I have no problem ever calling the school to ask a question. It's not about being a nervous parent, it's about being an involved parent. I don't get how people confuse the two. Knowing the people who are around my kids on a daily basis benefits all of us - and that's the comments from the people I know at their schools. Maybe 10-20 years ago it was different, but communication is the key to success, in my world.