The political authorities were overconfident, and neglected warnings.
Regardless of how much you know about body language, I caution you not to be overconfident in your knowledge as it applies to a specific person - especially someone you don't know well.
Qui-Gon had a great deal on his mind - he worried about Obi-Wan - I believe he rushed ahead for this reason, not be because he was overconfident.
There is a fine balance between nervousness in guys who are too shy and guys who are overconfident and behave like a girl owes them a kiss.
The success of the Axis forces may well have led their leaders to become overconfident.
