I have had the same experience in watching some of my friends trying to ride my trike. The manner of steering is contrary to what we have learned to do on a bicycle. In fact, I think that bike riding/handling is done on a subconscious level to a great extent. Hence the difficulty that some experience when they try to ride a trike. The new rider is operating on that level and not aware of why the trike can't do what he/she wants it to do. It is good for a laugh and most cyclists catch on quickly though some seem to never learn.
Paul Patzkowsky Longmont, Colorado