The Moro reflex is when they are startled and throw their arms out and then bring them together as if to clasp something, and maybe open their eyes and cry. My child development book says it goes away in the first months of life. But even adults will throw their arms out if they feel they are falling. If someone unfamilar is holding her or she is unsecure feeling she may just be reacting to a fear or feeling of falling.(like you said someone was putting her down) As always I say go with your instinct, if you think she is ok then don't worry. If there is something that bothers you get it checked out. (but not by a dr. or anyone else you don't like) Just 'cause he made it through med. school doesn't mean he knows what he is talking about.