So…many…characters… it was hard to fit them all in the frames.

This was a case of the party not getting a high enough Perception check to see details of a target dummy, and I explicitly mentioned a dome like metal object sitting next to it.  They thought it was a shield (correct), but not that it was covering a kobold hide-hole.  For a light-sensitive race, makes sense for them to stay put in the shade, does it not?