Both
genjichan and
aeriolewinters have a point. Lacus' disappearance does causes confusion, and when real-Lacus appeared in Orb, it causes even more confusion as real Lacus didn’t clearly explain the situation during the broadcast.
As for me,
Lacus’ function in SEED universe was to be a holy maiden most of the time. She was pictured as a flawless character (although she lacks character to begin with). Always beautiful, always dignified, can be a leader when it needed, guarded by bishounens and never got killed. If I should draw a comparison, her character is similar to
Saori Kido/
Athena from Saint Seiya. Only, Athena can’t sing.